Methods and compositions for producing capsicum plants with powdery mildew resistance

ABSTRACT

The invention relates to pepper plants and lines having resistance to Powdery Mildew, caused by the fungus  Leveillula taurica . The invention also relates to parts of pepper plants from lines having Powdery Mildew resistance, including seeds capable of growing pepper plants with Powdery Mildew resistance, and fruit. Methods for the identification, use and breeding of Powdery Mildew resistant pepper plants are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 61/529,205, filed Aug. 30, 2011, which is incorporated herein byreference in its entirety.

INCORPORATION OF SEQUENCE LISTING

The sequence listing that is contained in the file named“SEM004US_ST25.txt” which is 18,583 bytes (measured in MS-WINDOWS),created Aug. 29, 2012, is filed herewith by electronic submission and isincorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention provides pepper plants having Powdery mildew fungalresistance and methods for obtaining such pepper plants.

Description of Related Art

Peppers are one of the most popular fruit-bearing plants grownworldwide. Pepper plants are grown in a wide range of climates, in openfields as well as in greenhouses. Peppers belong to the genus Capsicum,of the nightshade family, Solanaceae (e.g. Capsicum annuum). The term“pepper” may refer to the plant as well as its fruit. Peppers arecommonly broken down into three groupings: bell peppers, sweet peppers,and hot peppers. Most popular pepper varieties fall into one of thesecategories, or as a cross between them. However, these groupings are notabsolute, as both “hot pepper” and “sweet pepper” encompass membersbelonging to several different species. Additionally, members of each ofthe groups may be different cultivars of the same species. For example,the bell pepper, the jalapeno pepper, and the “That sweet” all belong tothe species Capsicum annuum L. Hot peppers, including some inediblevarieties, are grown for edible as well as ornamental and medicinaluses. While there are pungent (i.e. “hot”) varieties of C. annuum, manywell known hot peppers are members of different species. For example,both the cayenne pepper and the Tabasco pepper are varieties of Capsicumfrutescens, while the hottest peppers, including the habanero and nagavarieties, are members of Capsicum chinense.

Pepper breeding efforts have focused in part on growing pepper plantsresistant to diseases such as Powdery Mildew (PM), caused by the fungusLeveillula taurica. Powdery mildew caused by the fungus Leveillulataurica exhibits a worldwide disease distribution and may affect peppersgrown under greenhouse or field conditions.

Symptoms of pepper Powdery Mildew caused by the fungus Leveillulataurica during the initial stages of infection may include visiblelight-green to bright-yellow blotches appearing on upper and lowersurfaces of leaves followed by a powdery, white growth caused by thesporulation of the fungus. Under some environmental conditions theseareas may later turn necrotic. Infected leaves may also curl upward andexhibit a visible powdery, white growth on the underside of leaves. Whenlesions are numerous, they often coalesce, resulting in generalchlorosis and leaf drop. The disease generally progresses from older toyounger leaves. Common commercial fruit production yield losses comefrom fruits on affected plants being overexposed to sunlight anddeveloping sunscald as well as reduced yield due to leaf loss.

Airborne conidia (asexual fungal spores) from previously infected cropsor weeds can be carried long distances by wind and act as initialsources of inoculum. The wide host range of these fungi exacerbatedisease spread and reduce the ability of agronomic practice to controldisease incidence. Disease control is commonly managed by application offungicides before infection or immediately after the first symptoms areobserved. In addition to the cost of pesticide application, there isincreasing social pressure to reduce the pesticide load in theenvironment.

There is a need for pepper varieties having resistance to Powdery Mildew(PM), caused by the fungus Leveillula taurica.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the present invention provides a method of identifying apepper plant of the genus Capsicum that displays improved resistance toPowdery Mildew, the method comprising: detecting in a first pepper plantat least one allele of a marker that is associated with the resistanceor improved resistance, wherein the marker is genetically linked within10 centiMorgans (cM) of markers NE0235653, NE0237841, NE0237985,NE0239990, or NE0240958, on pepper chromosome 4. In one embodiment,there is provided such a method, further wherein the marker is localizedwithin a chromosomal interval defined by and including the terminiNE0235653 and NE0240958 on pepper chromosome 4. In another embodiment,the marker is localized within a chromosomal interval defined by andincluding the termini NE0236790 and NE0237985 on pepper chromosome 4. Inyet another embodiment, the marker is localized within a chromosomalinterval defined by and including the termini NCANN005704058 andNCANN005704049.

In a particular embodiment the Powdery Mildew causal agent is Leveillulataurica. Provided in another embodiment is such a method wherein theresistance or improved resistance is assayed by exposing the plant toPowdery Mildew and identifying plants with reduced sporulation of L.taurica, relative to control plants.

In certain embodiment of the method, the detecting comprises detectingat least one allelic form of a single nucleotide polymorphism by PCR,single strand conformational polymorphism analysis, denaturing gradientgel electrophoresis, cleavage fragment length polymorphism analysis,TAQMAN assay, and/or DNA sequencing.

In another embodiment of the method, at least one allele of a markerassociated with resistance to Powdery Mildew is in pepper line PBC167,or a progeny plant thereof. Yet another embodiment comprisesphenotypically assaying said first pepper plant or a plant isogenicthereto for resistance to Powdery Mildew infection. Still anotherembodiment of the method comprises selecting the first pepper plant froma population of pepper plants based on the presence of said allele of amarker that is associated with the resistance or improved resistance toPowdery Mildew infection. In a particular embodiment, the method furthercomprises crossing the selected first pepper plant or germplasm with asecond pepper plant to obtain a progeny plant of a subsequentgeneration. The method may further comprise backcrossing the progenyplant of a subsequent generation and at least one further subsequentgeneration thereof to a recurrent parent until a backcrossed progenyplant is produced that comprises said improved resistance to PowderyMildew.

In certain embodiments of the method, the marker is selected from thegroup consisting of NE0235653, NE0238847, NE0237736, NE0236986,NE0236080, NE0237755, NE0239177, NE0238603, NE0238046, NE0237823,NE0230886, NE0240044, NE0237442, NE0238362, NE0238536, NE0236808,NE0238448, NE0241383, NE0240496, NE0237841, NE0239164, NE0240741,NE0236790, NE0238624, NE0240275, NE0238899, NE0238734, NE0240256,NE0237985, NE0239638, NE0239147, NE0240589, NE0237975, NE0239291,NE0235654, NE0238449, NE0240786, NE0239990, NE0231151, NE0240438,NE0237121, NE0238426, NE0235272, NE0237901, NE0237351, NE0241057,NE0237348, and NE0240958.

In some embodiments of the method, the marker is selected from the groupconsisting of NCANN005704058, NCANN005704056, NCANN005704052, andNCANN005704049.

In other embodiments the marker is one or more markers selected from thegroup consisting of NE0237823, NE0237442, NE0236808, NE0238624,NE0236790, NE0237985, NE0239147, NE0240438, and NE0237348. In particularembodiments the marker is NE0236790 or NE0237985. Further, the markermay map within 35 cM, 20 cM, 10 cM or 1 cM of a QTL which confersresistance to Powdery Mildew.

Another aspect of the invention relates to an agronomically elite pepperplant produced by the method described above, or an agronomically eliteprogeny plant thereof, that comprises said marker and chromosomalinterval conferring resistance to Powdery Mildew. In one embodiment thechromosomal region conferring resistance to Powdery Mildew comprises amarker allele present in PBC167. Thus a particular embodiment of theinvention provides a pepper plant wherein the chromosomal region isintrogressed from PBC167.

In certain embodiments the pepper plant is further defined as comprisingan allele from PBC167 at one or more of markers NE0235653, NE0238847,NE0237736, NE0236986, NE0236080, NE0237755, NE0239177, NE0238603,NE0238046, NE0237823, NE0230886, NE0240044, NE0237442, NE0238362,NE0238536, NE0236808, NE0238448, NE0241383, NE0240496, NE0237841,NE0239164, NE0240741, NE0236790, NE0238624, NE0240275, NE0238899,NE0238734, NE0240256, NE0237985, NE0239638, NE0239147, NE0240589,NE0237975, NE0239291, NE0235654, NE0238449, NE0240786, NE0239990,NE0231151, NE0240438, NE0237121, NE0238426, NE0235272, NE0237901,NE0237351, NE0241057, NE0237348, and NE0240958.

In other embodiments the pepper plant is further defined as comprisingan allele from PBC167 at one or more of markers NCANN005704058,NCANN005704056, NCANN005704052, and NCANN005704049.

In some embodiments the invention provides a part of the pepper plant orprogeny plant, including a seed capable of producing such a plant, andfruit.

In another aspect, the invention provides a pepper plant comprising atleast a first introgressed chromosomal interval conferring resistance toPowdery Mildew, wherein the interval is a Powdery Mildew resistancecontributing QTL on pepper chromosome 4 between markers NE0235653 andNE0240958. In one embodiment the interval is a Powdery Mildew resistancecontributing QTL on pepper chromosome 4 between markers NE0237823 andNE0240438. In another embodiment the interval is a Powdery Mildewresistance contributing QTL on pepper chromosome 4 between markersNE0236808 and NE0239147. In yet another embodiment the interval is aPowdery Mildew resistance contributing QTL on pepper chromosome 4between markers NE0236790 and NE0237985. In one embodiment the intervalis a Powdery Mildew resistance contributing QTL on pepper chromosome 4between markers NCANN005704058 and NCANN005704049.

In certain embodiments the pepper plant is defined as an agronomicallyelite plant displaying a trait selected from the group consisting of:enhanced plant vigor, altered leaf shape, altered plant height,determinacy, altered time to maturity, increased fruit size, blockyfruit shape, tapered fruit shape, altered fruit color, altered fruitweight, increased fruit pungency, reduced fruit pungency, enhanced fruittaste, enhanced surface appearance; altered seed number, altered seedsize, altered locule number; altered pericarp thickness and toughness,improved shelf life enhanced fruit yield, adaptation to field growth,adaptation to greenhouse growth, and resistance to one or more diseasesor disease causing organisms, relative to a control pepper plant. Insome embodiments the pepper plant is homozygous for said chromosomalinterval.

Another aspect of the invention relates to a method of producing apepper plant of the genus Capsicum that displays improved resistance toPowdery Mildew, the method comprising: introgressing at least a firstchromosomal interval that confers the improved resistance to PowderyMildew, wherein the chromosomal interval maps to a position between thesequence represented by marker NE0235653 and marker NE0240958, or thechromosomal interval maps to a position between the sequence representedby marker NE0235653 and marker NE0237348, which each map toapproximately 7.13 cM and 45.27 cM, respectively, on the genetic map ofthe linkage group termed pepper chromosome 4. In one embodiment themethod the introgressing comprises: a) assaying pepper plants for thepresence of at least one allele of a marker genetically linked to achromosomal interval that confers resistance to Powdery Mildew; and b)selecting at least a first pepper plant comprising the allele and thechromosomal interval that confers resistance to Powdery Mildew, whereinthe chromosomal interval maps to a position between the sequencerepresented by marker NE0235653 and marker NE0240958, or the chromosomalinterval maps to a position between the sequence represented by markerNE0235653 and marker NE0237348, which map to approximately 7.13 cM and45.27 cM, respectively, on the genetic map of the linkage group termedpepper chromosome 4; and c) self-pollinating the first pepper plant orcross pollinating the first pepper plant with a second pepper plant toproduce at least a first progeny pepper plant comprising the chromosomalinterval.

In certain embodiments of the method, selecting the first pepper plantfurther comprises selecting the plant based on the presence of aplurality of marker alleles that map to a position between the sequencesrepresented by markers NE0235653 and NE0240958, or the chromosomalinterval maps to a position between the sequence represented by markerNE0235653 and marker NE0237348, which map to approximately 7.13 cM and45.27 cM, respectively, on the genetic map of the linkage group termedpepper chromosome 4. The method may also further comprise the step of d)selecting a progeny plant comprising the allele which is linked withresistance to Powdery Mildew and self-pollinating, backcrossing with arecurrent parent or cross-pollinating the progeny plant with a thirdpepper plant to produce additional progeny plants. The method may alsofurther comprise repeating step (d) about 2-10 times.

In another embodiment of the method, the alleles are from markersselected from the group consisting of NE0238847, NE0237736, NE0236986,NE0236080, NE0237755, NE0239177, NE0238603, NE0238046, NE0237823,NE0230886, NE0240044, NE0237442, NE0238362, NE0238536, NE0236808,NE0238448, NE0241383, NE0240496, NE0237841, NE0239164, NE0240741,NE0236790, NE0238624, NE0240275, NE0238899, NE0238734, NE0240256,NE0237985, NE0239638, NE0239147, NE0240589, NE0237975, NE0239291,NE0235654, NE0238449, NE0240786, NE0239990, NE0231151, NE0240438,NE0237121, NE0238426, NE0235272, NE0237901, NE0237351, and NE0241057.

In certain embodiments of the method, the marker is one or more markersselected from the group consisting of NE0237823, NE0237442, NE0236808,NE0238624, NE0236790, NE0237985, NE0239147, NE0240438, and NE0237348. Inparticular embodiments the marker is NE0236790 or NE0237985.

In one embodiment, the marker is one or more markers selected from thegroup consisting of NCANN005704058, NCANN005704056, NCANN005704052, andNCANN005704049.

The method may also comprise assaying the pepper plants by PCR, singlestrand conformational polymorphism analysis, denaturing gradient gelelectrophoresis, cleavage fragment length polymorphism analysis, TAQMANassay, and/or DNA sequencing.

In some embodiments the chromosomal interval that confers resistance toPowdery Mildew confers a reduction of Leveillula taurica sporulation ofat least, or greater than, 25%, relative to a nonresistant controlpepper line.

Embodiments discussed in the context of methods and/or compositions ofthe invention may be employed with respect to any other method orcomposition described herein. Thus, an embodiment pertaining to onemethod or composition may be applied to other methods and compositionsof the invention as well.

As used herein the terms “encode” or “encoding” with reference to anucleic acid are used to make the invention readily understandable bythe skilled artisan however these terms may be used interchangeably with“comprise” or “comprising” respectively.

As used herein the specification, “a” or “an” may mean one or more. Asused herein in the claim(s), when used in conjunction with the word“comprising”, the words “a” or “an” may mean one or more than one.

The use of the term “or” in the claims is used to mean “and/or” unlessexplicitly indicated to refer to alternatives only or the alternativesare mutually exclusive, although the disclosure supports a definitionthat refers to only alternatives and “and/or.” As used herein “another”may mean at least a second or more.

Throughout this application, the term “about” is used to indicate that avalue includes the inherent variation of error for the device, themethod being employed to determine the value, or the variation thatexists among the study subjects.

Other objects, features and advantages of the present invention willbecome apparent from the following detailed description. It should beunderstood, however, that the detailed description and the specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings form part of the present specification and areincluded to further demonstrate certain aspects of the presentinvention. The invention may be better understood by reference to one ormore of these drawings in combination with the detailed description ofspecific embodiments presented herein.

FIG. 1: Marker Regression Results. A QTL (Quantitative trait locus orloci) is detected on Chromosome 4 with the following methodology: R/qtlfunction scanone (method=mr) was used to scan for single QTL across thewhole genome. Genome wide 1000 permutations were generated, 5% falsediscovery rate was utilized as significant threshold.

FIG. 2: Interval Mapping Results. A QTL on chromosome 4 was identifiedby all four sets of phenotypic data at almost the same location byinterval mapping using a non-parametric model for adjusted phenotypicdata at 1 cM intervals. LOD score significance was based on the 5% alphathreshold obtained with 1,000 permutations genome-wide.

BRIEF DESCRIPTION OF THE SEQUENCES

TABLE 1 Sequences used for design of genetic markers on chromosome 4.SEQ PBC167- ID derived NO. Marker Pos (cM) genotypeSequence used for marker design  1 NE0235653 7.13060677 GGATACTAAATCCAATAGTGCTCTTCCGCTGAAAGTTCATAATAGCCTGTAGATTTGAAAGA[A/G]GCAAGAGGTTAATCCAAATGAATTCGCGATGAAAAGCAGAATAAACGAAACCCGG GACTT  2 NE0236986 9.093390743TT AATAATTTATAGCTCCACAAATAGTCGATAAGTGGTTTAGATCAAAAAGTTGAAAAGTCT[T/C]TCTTACACTTTGTGCCAAGTCAAAGGCAGTGGCGGATCTACATACAATTCAAGGGG TTCA  3 NE0236080 9.157834477 GGAATTCCATTAGAACAGGTTCCATCAGAGCAGCAAAAGATTGTTCAACTATGCAGGCAGCT[A/G]AATAGGCCTGTTATAGTTGCTTCCCAGTTGCTGGAATCTATGATTGAATACCCTATTC CC  4 NE0239177 10.12474833 AACAATTTGCAAGGGAAAATCCAGCCTCCATGATGACTTATCACAGGTCGTAAACACTGTGT[A/G]GTCAATGTAGAAACTG TAAAAAAAAAAAAAnnCATTAACTAGACAA 5 NE0238603 10.89286968 CC GAGATCAAATGATTCAGACAAATAAAGAATACTAAAAGAAAGTAACATACAGTAAGAGA[A/C]ACATGTGAAACAATGTAAGACAATTAAGAGAAGGGTGAGAAAGCCCACCCCTCCA CGTGC  6 NE0238046 11.0627144 GGTGAnGTCTTTGGGTAGGAATCCTAAATAGAAATTTGTGCAGTGGAGAAGTACGTCCTGTC[A/G]AAGGAATTGGGAAGTCACTGAGTGTCGGACAAGTTGTATGGGCTCCATCTGGTGAA GGCT  7 NE0237823 11.56502861TT GTAACTGACGTAAGGGTAGATCCAAGATTTGAACATTATGTATTCGAGTTAGACTTTCTA[T/G]TGTAGTCCATTTGGTTTATTTATGACTCGAAACCTATTATTTGCACTCGTTTAGTAAAC A  8 NE0240044 12.04911329 TTCGTTCCAAGTACCAACTCATCCACACAGTACGTACACACAAGGGCGTGGATGAAAGGAGC[A/T]ATGGCTGTGTGTTCCGGGAGGAGGAAGAGAAGGAGGAGGTAGGCGTTGCCCTGTC GAAGG  9 NE0237442 13.39042803AA GCCTTCGGAAATCCAAATGTGCCTGGTGCTGGTTATGGTAGCGGTCAAGCTGGTGGATC[A/G]AGAAGCTCGTGGGGTTCTCAGGGTCCTTCTGGATATGGGAACATGGGCTATGGTAAT GCA 10 NE0238536 13.910493 AAGTGGTATGGGTGGTGGAAGTTACCAGGGGTATGGTGCATCTGGTGACAATCCCAGTTCTT[A/G]TGACAGAATGGATACCAACAGATACATGCAGTCACAAAACACTGTAGGTGGCTATC CACC 11 NE0236808 14.10971525TT GCCATAGTTAAATAGGTTCTCCTTCTGCTAATGTACATCATCTATGAAATTTAACATCTG[T/C]ATAATGCAGGTGCCTCCTACTTTGAGATTTGTGATGGATGGTGAAATGCCCGATTA 12 NE0238448 14.10971525 GGCACACAACCGATACTTACTATTnCAGAAAGTCACTTnCTTnGCAACCCTCCGGGGAAGTT[A/G]GTCACTTTGTCAATCAGAAATGCAGAATTTAACCAAGAATACCAAGCGGCCGTTTCC TCA 13 NE0241383 14.10971525 TTGATATAGGAGTATCATGGAAGTTGTGCCCTTTGATATGGTATGCGTGGAACCATTTGATC[T/C]ACATTTGTCCAGTTTATGCTCTAAGTCCCAGCATATCTTAGCAATAGCAGCCCTGTT ACA 14 NE0240496 14.78769275 CTCTATTGGGAAGCCTCCCACCAAACATATGTTCTATCTTACCCAACGTTGAAAGCGTTTAT[T/C]TGGCCTATACCAATTTT GCTGGGACTATTCCTCATTCCATC 15NE0237841 16.76424258 GG ACAGAATTGGTAGCCTTGATCACCCnGCTTCGGGTCCTGGTGACATGGTGGAACATTTGC[A/G]GCCAGAAACTGAGTCATTTACTGAGGTTTTACTTGCAAAGTTTGTCCGAATGCTCCA GAA 16 NE0239164 18.19035298AA TGACCTTTATAGTnnAAAAAAAnTTAAAAnGGACAAGAAATGGAAAGGGAACAAAGAAGA[A/G]TATCAGCAGCTTATCTATGTTTAACAAATTATGACCTCCATTAGCTTTTATATTAAT AAA 17 NE0236790 21.56183958GG CGATACATGCGCACCACTCGACATCTTTTGTGGTTCTCAAGATAACAATCGCAGGTAACA[T/G]CATCTGTAAATCCAATAGAACAACTTGGnGGTAATAATATTCCCTnAGAACACCCA AGCA 18 NE0238624 21.56183958GG TGGAATCAAGGGTCAGGAAGACTGAAATGTTGTATGCCGAAGGTCGTCAGCTGAAAGTGA[A/G]TCTAAGTCTTTTAATACTTAGAAAAATTTTCATACTTTTCAAGACTAAGTGCACTCT ACT 19 NE0240275 21.56183958GG CnGGGTTGGGGnAAGGGCTGAATCTTATAGTTCTTTCTGTGTGTCAAGTTAACGCCTCGT[A/G]GAGTCACTTACGATCTCTTCGTTTCCATTTTTCTTCTTGTTAAAGAATGAAnTTGGGTC T 20 NE0238899 24.87135151 GGAAAATTGCCTTAGTACGAATTAATACTCTTATATATTCTCAAAAGACATATACCCAGACC[A/G]TACTTGTGGGATTACACCGGCTATGTTGTGGTTGTTTTGTGAAGACATATTTAAGTAC TC 21 NE0238734 24.87248992 GGGTTAAGCTTCTGTGAAGCCAAAAGTnTTTTTTTnnCGAAGTGTTTAGTTAAAAAAGTTGC[A/G]TTGTTTGGCCAAGCTTTTAGGAAAAAGATAAGTATTTCGAGTCGTTGTAGAAACTGC ACT 22 NE0240256 25.1081287 CCCTGTTCAAGAGCAATTCAGTCATTTGTTCTTCAGGTAATCTTGTTTATTCCCAAATTGTG[C/G]CAATCAATTTGGTTCTCATCATTGGTATCAGAGACCTAATCATCTGACCTGTGCGATGG G 23 NE0237985 25.17303092 CCTACACnGGTAAAACTGACAAGGCATCAGCGTTAGCCAATAATGAACTTTTAGCGCGGAAC[T/C]TCAAGTGACCAAGTGCATGAAACCAAATCAAGAAGGTAAAGATATGnTGATCACCT GAAT 24 NE0239638 25.88460917GG TGGATATAGGAAAGATCACTTAGAAATTCAACAATCTTTTTCGTCTTTAAGAGCCTGTAG[A/G]CTTCTTTAGCATCTACACATCAAAATTCTCCAGACATTTCAAATTATATACAGTCCA CGA 25 NE0239147 26.81001479 CCACTCTTTTATTCGTAATGTTCATAGACGAAAGAGACGATCCTTCGCTCCTGTGAGCAGGA[T/C]GGTGTTCCAATGTGCAAGGCCCTTTCCTGAAGAGGTCGAAAATTCACGACCCATTCA TAG 26 NE0240589 29.49618369 GGTAAGTACAAGTTTAAGGATTCAAGTTATCTCTTAAATTAGCTTTCAGAACATGATGACAT[T/G]CTTTCTGCTTTGCGATGGGACAGATGGAATAnTCAAGTCATGTTGACTTGAT 27 NE0237975 30.80785657 GGAATAATGACATTCGATTTGTCAGCAACTAAATCAAAGCACTCCATCAAGCAACAATAAGA[T/G]ATCCGGACTTTCATCCGCATGCACCCTCACAGCAAGAAAGTTCCCCATACTACTTAC ACT 28 NE0239291 31.51094171 AAGTTTTTCCAATGTATCCACCAAATACAGTCATGCCTTTTGTATATTGGGATCAACCTA[A/G]TGTGTTCGCGCCAGTTCATTATCGCTCTTCTTATAGATGTATCGCACCTGGAAGTTGCAT 29 NE0238449 34.38657122 TTCTTTTTCTCTTATTnCCTTTTnATTTTCTTGTTTTGCTACTAAAAGCTTGAAGTTCTATT[T/G]TGCAATGTGCATACTTGCTTGAAGTCTCGTATTCACATGTTAAGACCTTCTCTTTAGAAA 30 NE0239990 34.8438471 CCCTTAGATCAAAAGTGAATACAACAAAAnGTTACCGGATGATTCCATTTCTAAGCCGACCA[T/C]ATCCACAGTAAACCCATATGTAGCAAGATAGAAATTGAAAACAATTATCACCGTAC ACAT 31 NE0231151 37.40944245 CTGCGCCCACGAACATTGCCGTGTTGGGAGTTACCAAGAGGCTGATGCAGAATGTACAAAGT[T/C]GTCTGCAATACGACACGTATGGTTTTGGAGACATTGTCTTATTTGGTAACGGGGAG AGAA 32 NE0240438 37.57094558CC CTCGTCTTCTTTCTTGATCTTTTAAGCACCGCGTTGATGAAATTTTTCGTGTTTTGCTTA[T/C]ACGAGTTGCATTTTTGAAATAATGTTAGTACGTTTTCAGATTATGATCATAGACTTCAA A 33 NE0237121 38.23427336 AAAATAGATCAAATCAACAATGGAGTTTAATTGAGAAAAAGAAGAAGCCAATAACAGATATC[A/G]CACAAATTTGGATTAGAATCGAGnAGAATGAGnACATAGATCACACnAATTCCTC AGAAT 34 NE0238426 38.41163895TT GGGGCGGAGCTAGAGTTGTAGTTACGGATTTAGCAGAACGAATGACACTTCTATAGGGCT[T/C]AAGTAGTTGGAATGAATCAGTTACTACTGATCAAAGTTATCAAAAGTTTTCGTATT GTCT 35 NE0235272 39.78935972TT CTTAAGAACACTCCCACTTCGGCTTAAGCACCATCGAAAAGACAAACTAGAACCAGCTCA[T/C]GCATACAATAAAAAGCATACACAAAAGTTACGAACCATAATTGGTCGTAAAATGG AGCAG 36 NE0237901 39.88201323TT TCTTGGAAAATCGATATCAGAAATGGAAATCCCATCGGGCTGTCAGGAGTTGACTCTTAG[T/C]TATCTTTGTGAAAGTTCCAAAnTGGGGTTTGGAGAGAGAGATGTTTTCGTGGATAAA GGT 37 NE0237351 40.28912425 TTCTTAAGAACACTCCCACTTCGGCTTAAGCACCATCGAAAAGACAAACTAGAACCAGCTCA[T/C]GCATACAATAAAAnGCATACACAAAAGTTACGAACCATAATTGGTCGTAAAATGG AGCAG 38 NE0241057 42.60970639CC CTTTATCGATGATTATCTGCTCTGGAGGTGTACGTTTCTCAACAGTTTCTATACTTGCAA[T/C]AGTTAGGCTTGATGTTGTTAAAGCCTAACTACTCGCAAACACACTCAGAACCAAATGC AA 39 NE0237348 45.2687706 TTATCGGCATCCTCAAGACTATCCATTGTTATAAAAGCAAAACCACGAGAGATACGAGAACG[T/C]GGCTCCACAACCAAGAAAGCTGATTTnACCTGGTCGACAGAAAGTAAAnGAAAAAn CTCA 40 NE0240958 45.2687706 CCCAGATATTTTCAGTAAAATCGTAATTAGATCCTTGAGATCTAACTGCACTCTAATGTCAC[T/C]TCAGGAGGCAAAACCAAAGAAGATTTTTTCTTCCAGCTCCATTAACTAAACCGCAT ACTC 41 NCANN00 21.56184 GGCAACCATCCCTCAACTAACGTGGGACACTTAACAATCTAC 5704058CGCACACCCAGGCCCGCCTACTAGAGCGTGGACGAAATAATGAGGGCCCTACATGGAGACGCACNGTAAGAGGGATGAGTCTGGCTCTGACCATGTGNNTAANTCAATCCTAAAAGCTATCTCATGAAGTGAGGATTGACCACNACCATACAAC[G/A]AGCTACAAACAAGCCATCCCTCAACCAATATGGGACATTAAACACTTCTTAAGTTCCAACTTANAAGTGTTGTCTTGAAG GATTGAGCAAGTGTCAA 42 NCANN0025.88461 CC ATGCATGAGGGCAATACAAGCNTTGAATCGAAATGACTG 5704056TTTAATCTCGTGGACTGTATATAATTTGAAATGTCTGGAGAATTTTGATGTGTAGATGCTAAAGAAGNCTACAGGCTC[C/T]TAAAGACGAAAAAGATTGTTGAATTTCTAAGTGATCTTTCCTATATCCACCCCTAAGCTGCCAGCGCTGGGGGTTCCTT TCTCTTGGTTGGCCTTCCTAG 43NCANN00 29.49618 CC CCGTTTTAACATATGTACATGGCTTGTCTTAGTTACTAATA 5704052TCATCTGATACCATGTGCAAACATGACTTGGGAATGTGGGACTTAATATACTTGTAACC[C/A]TGTGTTTTGTTATTGAAATTAAAGTTCAGTGTTATGTTTGTTTAAAACGGCCACTNGGTACATGTTATACNGCTCTTGGTCTAAGCTCTTATCTACATACTATAAATAACTTTTTTTGTTCTTGGTTTCTATCACCAATT ATTATTTTATC 44 NCANN0031.51094 TT ATTTCTGGATTTCTACTTGTAAAAGGGAAGCCCGGTGCAC 5704049TAAAGCGCCCGTTATGCAAGGGGGCCGGGGAAGGTTCAGCCTGCAACGGTCCATTGTACG[T/C]AGCCTTANCCTGCATTTCTNCAAGAGGCTGTTTCCACAGCTTGAATCCGTGACCTC CTGGTCACATGGCAACAACTTTACCCAWhere n = A, C, T, or G.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides methods for identifying pepper plants, of thegenus Capsicum, having resistance or increased resistance to PowderyMildew caused by the fungus Leveillula taurica. Such pepper lines can bereferred to as Powdery Mildew resistant pepper varieties. Methods ofbreeding Powdery Mildew resistant pepper lines are further provided.Also disclosed herein are molecular markers that are linked toquantitative trait loci (QTL) contributing to Powdery Mildew resistance.Through use of the markers, one of skill in the art may increase thedegree of Powdery Mildew resistance in pepper or select plants for anincreased predisposition for Powdery Mildew resistance. In particularembodiments, the methods are performed on progeny pepper plants ofpepper line PBC167, such as members of the PBC167 X SBY 99-1179 mappingpopulation disclosed herein, or progeny thereof. The QTL identified inthis manner may be combined with one or more other QTL that alsocontribute to Powdery Mildew resistance, as desired. A QTL wasidentified here which corresponds to the location between approximately7 to 45 centiMorgans (cM) on pepper chromosome 4 and is flanked bymarkers NE0235653 and NE0240958 and which has a significant effect onPowdery Mildew resistance in pepper. This QTL significantly reduces aplant's Powdery Mildew disease rating in a Powdery Mildew pathology testas described herein, for instance in the PBC167 X SBY 99-1179 mappingpopulation genetic background, when grown in multiple tested geographiclocations.

The definition of this QTL allows the use of specific molecular markers,such as those disclosed herein, in a plant breeding program tointrogress a Powdery Mildew resistance trait to agronomically elitepepper lines. It also allows movement of the trait within agronomicallyelite pepper lines. Marker-assisted introgression involves the transferof a chromosomal region, defined by one or more markers, from onegermplasm to a second germplasm. An initial step in that process is thelocalization of the trait by mapping, which is the process ofdetermining the position of a genetic element relative to other geneticelements and genetic markers through linkage analysis. The basicprinciple for linkage mapping is that the closer together two featuresare on the chromosome, the more likely they are to be inheritedtogether. Briefly, a cross is made between two genetically compatiblebut divergent parents relative to a trait under study (e.g. PowderyMildew resistance). Morphological, genetic or molecular markers are thenused to follow the segregation of traits under study in the progeny fromthe cross, often termed a “mapping population.” The current inventionrelates to the introgression in a pepper of a chromosomal region, e.g.,a mapped QTL, which is capable of causing a plant to be more resistantto the onset and progression of pathogen-induced disease symptoms causedby Leveillula taurica. The inventors identified a chromosomal regionresponsible for Powdery Mildew resistance and used marker assistedbreeding to introgress these specific linkage blocks into other peppergermplasm that lacked such resistance to Powdery Mildew. In certainembodiments of the invention, the process for producing a Powdery Mildewresistant pepper plant or line comprises introgressing at least onechromosomal locus mapping to chromosome 4 from a more Powdery Mildewresistant pepper plant, line, or variety into a less Powdery Mildewresistant pepper plant, line, or variety. In specific embodiments, themore Powdery Mildew resistant pepper plant, line, or variety is PBC167,or a progeny plant thereof containing the disease resistant trait.

Introgression of a particular chromosomal region or set of regions intoa plant genotype is defined, for example, as the result of the processof backcross conversion. Additional examples of breeding techniquesintended to reach the same result include pedigree selection anddihaploidization of an F1. A plant genotype into which a DNA sequencehas been introgressed may be referred to as a converted genotype, line,or variety. Such genotype, line, or variety may be an inbred or a hybridgenotype, line, or variety. Similarly a plant genotype lacking saiddesired DNA sequence may be referred to as an unconverted genotype,line, or variety. During breeding, the genetic markers linked toenhanced Powdery Mildew resistance may be used to assist in breeding forthe purpose of producing pepper plants with increased resistance toLeveillula taurica. A skilled worker would understand that theintrogression of a Powdery Mildew resistance trait into a pepper plantmay be monitored by visual clues such as by use of a disease resistancetest with a disease rating scale as described herein, or by monitoringand breeding for the presence of molecular markers as described herein(i.e. marker assisted selection), or both.

Localization of such markers to specific genomic regions further allowsfor use of associated sequences in breeding and to develop additionallinked genetic markers. It will be understood to those of skill in theart that other markers or probes which more closely map the chromosomalregion as identified herein could be employed to identify plantscomprising a desired QTL for Powdery Mildew resistance. The chromosomalregion of the present invention facilitates introgression of increasedPowdery Mildew resistance from Powdery Mildew resistant germplasm, suchas PBC167 or progeny thereof, into other germplasm, preferablyagronomically useful pepper germplasm. Linkage blocks of various sizescould be transferred within the scope of this invention as long as thechromosomal region enhances the Powdery Mildew resistance of a desirablepepper plant, line, or variety. Accordingly, it is emphasized that thepresent invention may be practiced using any molecular markers thatgenetically map within the identified region, provided that the markersare polymorphic between the parents.

In particular embodiments, these markers may be genetically linked tothe described QTL for Powdery Mildew resistance which is located onpepper chromosome 4, for instance as defined in the genetic map of Wu etal. (Theor. Appl. Genet., 2009, 118(7):1279-93). In certain embodiments,the markers are within 50 cM, 45 cM, 40 cM, 35 cM, 30 cM, 25 cM, 20 cM,15 cM, 10 cM, 5 cM, 3 cM, 1 cM, or less, of the QTL defined onchromosome 4, at 7.7-42.7 cM based on analysis of the PBC167 X SBY99-1179 mapping population as described herein. In particularembodiments, the markers used to follow the presence of the QTL forPowdery Mildew resistance which is located on pepper chromosome 4 areselected from the group consisting of: NE0235653, NE0238847, NE0237736,NE0236986, NE0236080, NE0237755, NE0239177, NE0238603, NE0238046,NE0237823, NE0230886, NE0240044, NE0237442, NE0238362, NE0238536,NE0236808, NE0238448, NE0241383, NE0240496, NE0237841, NE0239164,NE0240741, NE0236790, NE0238624, NE0240275, NE0238899, NE0238734,NE0240256, NE0237985, NE0239638, NE0239147, NE0240589, NE0237975,NE0239291, NE0235654, NE0238449, NE0240786, NE0239990, NE0231151,NE0240438, NE0237121, NE0238426, NE0235272, NE0237901, NE0237351,NE0241057, NE0237348, NE0240958, NCANN005704058, NCANN005704056,NCANN005704052, NCANN005704049, or other genetic markers linked to theQTL. The associated presence of alleles conferring resistance to PowderyMildew may be identified by use of well known techniques, such as bynucleic acid detection methods utilizing probes or primers comprising asequence selected from the group consisting of SEQ ID NOs:1-44. Incertain embodiments, the method comprises detecting the presence of oneor more single nucleotide polymorphisms (SNPs) given in one or more ofSEQ ID NOs:1-44.

In certain embodiments, the Powdery Mildew resistance QTL of chromosome4 is defined as spanning the region defined by SNP marker NE0235653 (mapposition 7.131 according to Table 7), to SNP marker NE0240958 (mapposition 45.269 according to Table 7).

The Powdery Mildew resistance QTL of the present invention has beendefined in a mapping population based on a cross of pepper lines PBC167and SBY 99-1179, as being located between genetic markers NE0235653 andNE0240958, at about 7 cM-45 cM in the linkage group, and as defined byanalysis of that mapping population (e.g. see Table 3). Further, one ofskill in the art would understand that assignment of such genetic mappositions may be affected by the mapping population being analyzed,including for instance the parent lines used, the marker density, andthe size of the population, each of which may affect the level ofrecombination which is seen, and thus the assigned genetic map position.An integrated genetic and physical map may be utilized to define theposition of a pepper QTL, such as one provided by Wu et al. (Theor.Appl. Genet., 2009, 118(7):1279-93), for instance relative to markerswith known genetic and/or physical map positions.

As used herein, a “hybrid pepper plant” includes a plant resultingdirectly or indirectly from crosses between populations, breeds orcultivars within the genus Capsicum. “Hybrid pepper plant” as usedherein also refers to plants resulting directly or indirectly fromcrosses between different species, varieties or genotypes.

As used herein, a “female parent” refers to a pepper plant that is therecipient of pollen from a male donor line, which pollen successfullypollinates an egg. A female parent can be any pepper plant that is therecipient of pollen. Such female parents can be male sterile, forexample, because of genic male sterility, cytoplasmic male sterility, orbecause they have been subject to manual emasculation of the stamens.Genic or cytoplasmic male sterility can be manifested in differentmanners, such as sterile pollen, malformed or stamenless flowers,positional sterility, and functional sterility.

As used herein, an “agronomically elite plant” refers to a genotype thathas a culmination of distinguishable and desirable agronomic traitswhich allow a producer to harvest a product of commercial significance.

As used herein, “cytoplasmic male sterility” refers to plants that arenot usually capable of breeding from self-pollination, but are capableof breeding from cross-pollination.

As used herein, a “part of the pepper plant” is further defined aspollen, an ovule, a leaf, an embryo, a root, a root tip, an anther, aflower, a fruit, a stem, a shoot, a seed, a protoplast, a cell, and acallus.

As used herein, “improved resistance” refers to a more resistant pepperplant score on a Powdery Mildew bioassay rating scale as compared to acontrol pepper plant with a similar genetic background but lacking theclaimed QTL region.

As used herein, “linkage” is a phenomenon wherein alleles on the samechromosome tend to segregate together more often than expected by chanceif their transmission was independent.

As used herein, a “marker” is an indicator for the presence of at leastone phenotype, genotype, or polymorphism. Markers include, but are notlimited to, single nucleotide polymorphisms (SNPs), cleavable amplifiedpolymorphic sequences (CAPS), amplified fragment length polymorphisms(AFLPs), restriction fragment length polymorphisms (RFLPs), simplesequence repeats (SSRs), insertion(s)/deletion(s) (“INDEL”(s)),inter-simple sequence repeats (ISSR), and random amplified polymorphicDNA (RAPD) sequences. A marker is preferably inherited in codominantfashion (both alleles at a locus in a diploid heterozygote are readilydetectable), with no environmental variance component, i.e.,heritability of 1. A “nucleic acid marker” as used herein means anucleic acid molecule that is capable of being a marker for detecting apolymorphism, phenotype, or both associated with Powdery Mildewresistance. Stringent conditions for hybridization of a nucleic acidprobe or primer to a marker sequence or a sequence flanking a markersequence refers, for instance, to nucleic acid hybridization conditionsof 5×SSC, 50% formamide, and 42° C. As used herein, “marker assay” meansa method for detecting a polymorphism at a particular locus using aparticular method, e.g. measurement of at least one phenotype (such as avisually detectable trait, including disease resistance), restrictionfragment length polymorphism (RFLP), single base extension,electrophoresis, sequence alignment, allelic specific oligonucleotidehybridization (ASO), random amplified polymorphic DNA (RAPD),microarray-based technologies, PCR-based technologies, and nucleic acidsequencing technologies, including whole genome sequencing, etc.

As used herein, a “desirable trait” or “desirable traits” that may beintroduced into Powdery Mildew resistant pepper plants by breeding maybe directed to the pepper fruit or the pepper plant. Desirable traits tobe introduced into pepper plants and pepper fruit may be independentlyselected. Desirable pepper fruit traits, e.g. as displayed byagronomically elite lines or cultivars, and that may be independentlyselected include, but are not limited to: fruit size, shape, color,surface appearance; seed number, seed size, locule number; pericarpthickness and toughness; taste and shelf life. Desirable pepper planttraits, e.g. as displayed by agronomically elite lines or cultivars, andthat may be independently selected include, but are not limited to:plant vigor, leaf shape, leaf length, leaf color, leaf number, plantheight, whether the plant is determinate or not, time to maturity,adaptation to field growth, adaptation to greenhouse growth, andresistance to one or more diseases or disease causing organisms.Improvement in such trait may be assessed by comparison with one or moreother pepper lines, including a parental line. Any combination ofdesirable pepper fruit traits, pepper plant traits, or pepper plant andfruit traits may be combined with a Powdery Mildew resistance trait.

As used herein, “polymorphism” means the presence of one or morevariations of a nucleic acid sequence at one or more loci in apopulation of one or more individuals. The variation may comprise but isnot limited to one or more base changes, the insertion of one or morenucleotides or the deletion of one or more nucleotides. A polymorphismmay arise from random processes in nucleic acid replication, throughmutagenesis, as a result of mobile genomic elements, from copy numbervariation and during the process of meiosis, such as unequal crossingover, genome duplication and chromosome breaks and fusions. Thevariation can be commonly found, or may exist at low frequency within apopulation, the former having greater utility in general plant breedingand the latter may be associated with rare but important phenotypicvariation. Useful polymorphisms may include single nucleotidepolymorphisms (SNPs), insertions or deletions in DNA sequence (INDELs),simple sequence repeats of DNA sequence (SSRs) a restriction fragmentlength polymorphism, and a tag SNP. A genetic marker, a gene, aDNA-derived sequence, a haplotype, a RNA-derived sequence, a promoter, a5′ untranslated region of a gene, a 3′ untranslated region of a gene,microRNA, siRNA, a QTL, a satellite marker, a transgene, mRNA, dsRNA, atranscriptional profile, and a methylation pattern may comprisepolymorphisms. In addition, the presence, absence, or variation in copynumber of the preceding may comprise a polymorphism.

As used herein, “genotype” is the actual nucleic acid sequence in anindividual plant. As used herein, “phenotype” means the detectablecharacteristics (e.g. level of Powdery Mildew resistance) of a cell ororganism which can be influenced by genotype.

As used herein, a “quantitative trait locus (QTL)” is a region of DNAthat is associated with a particular phenotypic trait.

Powdery Mildew resistance of a pepper plant provided herein canpotentially be defined as complete resistance or partial resistance. ThePowdery Mildew resistance of a pepper plant provided herein can bemeasured by any means available in the art.

In one aspect, Powdery Mildew resistance of a pepper plant is determinedby using a disease rating of percent leaf coverage of Powdery Mildewspores developed after inoculation or infection with Powdery Mildew onpepper leaves using a scale of symptoms of 0%, 10%, 20%, 30%, 40%, 50%,60%, 70%, 80% and greater than about 90% sporulation covering the leafarea. A disease rating of 0% indicates a completely resistant plant.

In another aspect, Powdery Mildew resistance is determined by obtainingdisease ratings of spore development after one or more rounds ofinoculation or infection with Powdery Mildew on pepper leaves and/orseedlings.

Resistance may be scored on an exemplary three point scale (where 1 isresistant and 9 is susceptible) as follows:

-   -   1=(High Resistance): No sporulation    -   5=(Intermediate Resistance): Very light sporulation usually        underneath the leaf    -   9=(Susceptible): White sporulation on the whole surface of        inoculated leaves

Resistance may also be scored on an exemplary 5 point scale (where 1 isresistant and 5 is susceptible) as follows:

Density sporulation: Spot per leaf: 0 = no visible sporulation 0 = Nospots 1 = few spores per spot, <10% 1 = 1 or 2 spots 2 = lightsporulation, 25% 2 = 3, 4 or 5 spots 3 = strong sporulation, easy to see25-50% 3 = more than 5 spots per leaf 4 = very strong sporulation 50-75%4 = 50% of leaf affected 5 = sporulation on upper and lower side of leaf5 = 90% of leaf affectedSporulation refers to the presence of visible powdery, white growth onleaf surfaces. As described here, this may be measured by visualperception of the percent of leaf area affected. Tests are evaluatedonce symptoms have developed on susceptible checks. PBC167 may be usedas a “resistant” control. Scores of 1-5 or 1-9 indicate varying levelsof resistance or susceptibility. On the 1-5 scale, a score of 1-2 afterone or more rounds of inoculation or infection, and preferably two ormore rounds of infection, indicates a resistant plant; a score of 3after one or more rounds of inoculation or infection, preferably two ormore rounds of infection, indicates a plant exhibiting intermediateresistance; a score of 4-5 indicates a susceptible plant.

Pepper lines having Powdery Mildew resistance, or partial resistance,demonstrate a reduced level of symptoms relative to a non-resistantcontrol pepper line after inoculation or infection with Powdery Mildew.The level of symptoms can be used as an indicator of Powdery Mildewresistance. Disease symptoms measured can be any disease symptomsassociated with Powdery Mildew infection. Symptoms can include thepresence of white or brown sporulation patches on the underside ofleaves, leaf yellowing or development of light-green to bright-yellowblotches that later turn necrotic on the upper sides of leaves, curlingof infected leaves, general leaf chlorosis or leaf drop. In one aspect,a Powdery Mildew resistant pepper line demonstrates a reduction ofsporulation patches of at least, or greater than, 10%, 20%, 25%, 30%,40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, or 98% relative to anon-resistant control pepper line. In other aspects, the leaves of aPowdery Mildew resistant pepper plant demonstrate less than 15%, or lessthan 10%, or less than 5%, or less than 2% symptomatic area when exposedto Powdery Mildew. In another aspect, the pepper plant belongs to apepper variety or cultivar, and in another aspect, the pepper plant isan inbred pepper plant.

In another aspect, the pepper plants and varieties provided hereindemonstrate little or no symptoms of sporulation after inoculation orinfection with Powdery Mildew. In some aspects, a Powdery Mildewresistant pepper plant demonstrates symptoms of sporulation on less than25%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3% 2%, or 1% of the pepperleaf surface.

Powdery Mildew resistant pepper plants may exhibit a delay in the onsetof symptoms of Powdery Mildew sporulation relative to a non-resistantcontrol pepper plant. In some embodiments, the Powdery Mildew resistantpepper plants exhibit a delay of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, or more days in the onset of symptoms of Powdery Mildewsporulation relative to a control pepper plant. In other embodiments,the Powdery Mildew resistant pepper plants exhibit a delay of at least 7or more days, 10 or more days, or 14 or more days in the onset ofsymptoms of Powdery Mildew sporulation relative to a control pepperplant.

In one aspect, the pepper plant is a seedling at the time of inoculationor infection. In some aspects, the pepper plant is a seedling at the 4,5, 6, 7, or 8 leaf stage of development when inoculated. In one aspect,disease symptoms can be measured at any time after pathogenic challengeof a pepper plant. In other aspects, symptoms can be measured 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or moredays after inoculation. In another aspect, the pepper plant is any ageof plant at the time of inoculation or infection.

In another aspect, disease symptoms can be observed after Powdery Mildewchallenge of an entire plant or a part thereof, for example, a plantcutting. Powdery Mildew resistant pepper plants of the present inventionmay exhibit an increase in fruit yield after inoculation or infectionwith Powdery Mildew relative to a control pepper plant inoculated withPowdery Mildew. In one aspect, the resistant pepper plants exhibit a 2%,5%, 10%, 15%, 20% or more increase in fruit yield, based upon the totalmass, number, or total volume of fruit, relative to a control pepperplant after one or more rounds of inoculation or infection with PowderyMildew.

The present invention provides for and includes pepper plants thatexhibit resistance to one or more isolates or races of Powdery Mildew.In some embodiments, the pepper plants of the present invention exhibitresistance to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more isolates or racesof Powdery Mildew.

The present invention provides for a seed of a pepper plant capable ofproducing a plant having Powdery Mildew resistance. In one aspect, thepepper plant can be an open-pollinated variety, a hybrid parent inbredline, or a male sterile line. In another aspect, the invention providesseed of a pepper plant capable of producing a hybrid pepper plant havingPowdery Mildew resistance.

The pepper plants of the present invention can be pepper lines adaptedfor greenhouse pepper production or for field pepper production. In oneaspect, the pepper plants of the present invention are adapted forgreenhouse pepper production.

The present invention also provides a hybrid pepper having PowderyMildew resistance. In another aspect, the present invention provides ahybrid pepper exhibiting Powdery Mildew resistance after inoculation orinfection with Powdery Mildew.

Agronomically elite pepper plants represent one aspect of the presentinvention. In one aspect, certain pepper agronomic traits, including,for example, fruit size, shape, color, weight, pungency, taste and fruityield may be important to the commercial value of the crop. Fruit sizeand shape, may be of particular interest if the peppers are grown forprocessing such as pickling. The present invention provides for a pepperplant having one or more traits selected from the group consisting of:

-   -   a. plants with prostrate, compact, erect growth habits;    -   b. plants that have glabrous stems or have sparse, intermediate        or abundant stem pubescens;    -   c. plants that have glabrous leaves or have sparse, intermediate        or abundant leaf pubescens;    -   d. plants with green or purple stems;    -   e. plants that have pendant, intermediate, or erect pedicle        position at anthesis;    -   f. plants that have white, green-white, lavender, blue or violet        corolla color;    -   g. plants with yellow, pale blue, blue, or purple anthers;    -   h. plants with white or blue filament colors;    -   i. plants having a stigma included within the anthers, at the        same level as the anthers, or exerted beyond the anthers at full        anthesis;    -   j. plants that are male sterile or male fertile;    -   k. plants that have low, intermediate or high fruit set;    -   l. plants with white, straw or cream, yellow, brown, dark brown,        or black seeds;    -   m. plants that have smooth, intermediate, or dentate calyx        margins;    -   n. plants that have or lack an annular constriction at the        junction of the calyx and peduncle;    -   o. plants that have declining, intermediate, or erect fruit        position;    -   p. plants that have white, green, yellow, orange, red, purple,        brown, or black immature fruit;    -   q. plants that have white, green, yellow, orange, red, purple,        brown, or black mature fruit;    -   r. plants with pepper fruit that is sweet, or has low (i.e.        mild), intermediate (i.e. medium) or high (i.e. hot or very hot)        pungency;    -   s. plants that have an average fruit length at ripeness that is        very short (less than about one cm), short (about 5 cm or about        2 to about 7 cm), medium (about 10 cm or about 7 to about 12        cm), long (about 15 cm or about 13 to about 25 cm) or very long        (greater than 25 cm or about 25 cm to about 40 cm);    -   t. plants with a fruit wall thickness (measured halfway between        the point of attachment of the stem and the blossom end) from        about 0.5 to 1.5 mm or from about 1 to about 2.5 mm or from        about 1.5 to about 4 mm or from about 2 to about 5 mm, or from        about 3 to about 6 mm, or from about 3.5 mm to about 7.5 mm;    -   u. plants that have an average fruit width at ripeness that is        about 0.3 to 1 cm, about 1 to 2 cm, about 2 to 4 cm, about 3 to        7, about 6 to 10, about 7 to 11 or greater than about 11 cm;    -   v. plants without persistent fruit or plants with persistent        fruit (fruit that persists and maintains an attachment to the        plant after ripening);    -   w. plants with pepper fruit having an average weight a ripeness        from about 1 to 5 g, 5 to 25 g, 25 to 50 g, 50 to 100 g, 100 to        250 g, 150 to 450 g, 200 to 500 g or 300 to 550 g.    -   x. plants with pepper fruit that is elongate, oblate, round,        conical or pointed, campanulate, or bell/blocky;    -   y. plants where the pepper fruit shape at the point of        attachment is acute, obtuse, truncate, cordate, or lobate;    -   z. plants where the pepper fruit has or lacks a neck at the base        of the fruit;    -   aa. plants where the blossom end is pointed, blunt, or sunken;    -   bb. plants where the pepper fruit has a smooth, slightly        corrugated, intermediate, or very corrugated cross section;    -   cc. plants with resistance to one or more multi-cellular pests        (e.g., nematodes and aphids);    -   dd. plants with resistance to diseases caused by one or more        bacteria or fungi (e.g., Xanthomonas sp. and Leveillula        taurica);    -   ee. plants with resistance to diseases caused by one or more        viruses (e.g., geminivirus, tobamovirus);    -   ff. plants having or lacking anthocyanins in unripe pepper        fruit;    -   gg. plants having or lacking anthocyanins in ripe pepper fruit;    -   hh. plants that are resistant or susceptible to low temperature;    -   ii. plants that are resistant or susceptible to high        temperature;    -   jj. plants that are resistant or susceptible to drought;    -   kk. plants that are resistant or susceptible to high soil        moisture;    -   ll. plants that are resistant or susceptible to high humidity;        and    -   mm. plants that shed fruit easily or do not shed fruit easily.

In some aspects, a pepper plant of the present invention may produce apepper fruit having a weight at harvest of about or greater than about1, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700,750, 800, 850, 900, 950, and 1000 grams. In other aspects, a pepperplant of the present invention produces a pepper fruit having a weightat harvest between about 1 and about 1000 grams, about 100 and about 900grams, about 200 and about 800 grams, about 300 and about 700 grams, orbetween about 400 and about 600 grams. Fruit weight is measured byweighing individual pepper fruit on a scale.

A pepper fruit attribute such as shape, weight, or size can be measuredor evaluated at a variety of times. In one aspect, an attribute ismeasured following growth in a growth chamber. In another aspect, anattribute is measured at the time of harvest. In yet another aspect, anattribute is measured after storage of the pepper fruit at ambientconditions for one day, two days, three days, four days, five days, sixdays, seven days, eight days, nine days, ten days, eleven days, twelvedays, thirteen days, two weeks, three weeks, four weeks, or five weeksafter harvest.

In one embodiment, a pepper fruit from a pepper plant having PowderyMildew resistance has an overall fruit quality rating of 1, 3, 5, 7, or9, where fruit quality is measured by visual inspection, with a scaleranging from 1=excellent through 9=poor: Rating 1=Excellent; 3=Aboveaverage; 5=Average; 7=Below average; 9=Poor; compared to an appropriatecommercial hybrid comparison grown in the area. Fruit quality includes,but is not limited to, fruit color, fruit shape, fruit length anddiameter.

A further aspect of the invention relates to tissue cultures of thepepper plants described herein. As used herein, the term “tissueculture” indicates a composition comprising isolated cells of one ormore types, or a collection of such cells organized into parts of aplant. Tissue culture includes, but is not limited to, compositionscomprising protoplasts and calli. Tissue culture also includes, but isnot limited to, compositions comprising plant cells that are present inintact plant tissues, or parts of plants, such as embryo, leaf,peduncle, pedicel, anther, meristem, tip and segments of root, stump andstem, explants, and the like. In one aspect, a tissue culture comprisesembryos, protoplasts, meristematic cells, pollen, leaves, anthers orcells derived from immature tissues of these plant parts. Means forpreparing and maintaining plant tissue cultures are well known in theart. Examples of processes of tissue culturing and regeneration ofpepper are described in, for example, Fillatti et al., 1987(Bio/Technology 5:726-730). In some aspects, tissue culture of thepepper plants described herein relates to the culture of protoplasts,calli, or plant cells, that are isolated from, or present in, intactparts of the Powdery Mildew resistant plants described herein. Inanother aspect, tissue culture refers to the culture of protoplasts,calli, or plant cells, that are isolated from, or present in, intactparts of plants of one or more Powdery Mildew resistant pepper plantlines described herein, for example from the PBC167 X SBY 99-1179population.

Once Powdery Mildew resistant plants are produced, the plants themselvescan be cultivated in accordance with conventional procedures. PowderyMildew resistant progeny may be obtained through sexual reproduction.The seeds resulting from sexual reproduction can be recovered from thefruit of Powdery Mildew resistant plants and planted or otherwise grownas a means of propagation. Powdery Mildew resistant progeny may also beobtained from Powdery Mildew resistant plants through asexualreproduction. Protoplast or propagules (e.g., cuttings, scions orrootstocks) can be recovered from Powdery Mildew resistant plants orparts thereof and may be employed to propagate Powdery Mildew resistantplants.

The present invention also provides for and includes a container ofpepper seeds in which pepper plants grown from greater than 50% of theseeds have resistance or partial resistance to Powdery Mildew. Inanother aspect, pepper plants grown from greater than 55%, 65%, 75%,85%, 90%, 95%, 98%, or 99% of the pepper seeds in the container havePowdery Mildew resistance. Another aspect of the invention relates toseeds from a pepper plant selected from the group consisting of thePBC167 X SBY 99-1179 population, and Powdery Mildew resistant progenythereof, wherein pepper plants grown from about 50%, or greater than50%, of the seeds have resistance or partial resistance to PowderyMildew.

The container of pepper seeds can contain any number, weight or volumeof seeds. For example, a container can contain about, or greater thanabout, 10, 25, 50, 200, 400, 700, 1000, 2000, 3000, or more seeds. Inanother aspect, a container can contain about, or greater than about, 1gram, 5, 10, 15, 25, 100, 250, 500, or 1,000 grams of seeds.Alternatively, the container can contain about or at least, or greaterthan, about 1 ounce, 2, 4, 8, 10 ounces, 1 pound, 2, 4, 8, 12 pounds ormore of seeds.

Containers of pepper seeds can be any container available in the art.For example, a container can be a box, a bag, a packet, a pouch, a taperoll, a foil, a pail, or a tube.

The present invention includes and provides for a container of pepperfruit from pepper plants having Powdery Mildew resistance. In oneaspect, the container contains about 2, 5, 10, 20, 40, 80, 100, or morepepper fruit. In yet another aspect, the present invention provides apepper branch having pepper fruit from a plant having resistance toPowdery Mildew.

One aspect of the invention relates to dried, or otherwise processed,pepper fruit, produced by a pepper plant having a genome that comprisesat least one genetic locus giving rise to Powdery Mildew resistance whenexpressed in a pepper plant. Processed pepper fruit includes, but is notlimited to fruit pulp, stewed peppers, canned, pickled, minced, sliced,ground, or crushed pepper fruit. In some aspects, the dried, pickled, orotherwise processed pepper fruit, is the fruit of a pepper plant of aline selected from the group consisting of the PBC167 X SBY 99-1179population.

The present invention provides for an inbred pepper plant havingresistance to Powdery Mildew, wherein the resistance is exhibited whenthe plant is in contact with Leveillula taurica. In one aspect, theinbred pepper plant is derived from accession PBC167, available from theUnited States Department of Agriculture (USDA; Beltsville, Md., USA)germplasm collection under PI640507.

The present invention includes and provides for Capsicum plants havingat least one allele linked to or conferring a Powdery Mildew resistancetrait. The Powdery Mildew resistant pepper plants can be eitherheterozygous or homozygous for the Powdery Mildew resistance trait. Inone embodiment, the Powdery Mildew resistant trait can be linked tovariations in a single gene (e.g., linked to one or more alleles of asingle gene). In another embodiment, the Powdery Mildew resistance traitcan be linked to variations at one or one or more QTL. In a yet anotherembodiment, the Powdery Mildew resistant pepper plants are homozygousfor the Powdery Mildew resistance trait.

The present invention provides progeny of pepper plants havingresistance to Powdery Mildew. As used herein, progeny include not only,without limitation, the products of any cross (be it a backcross orotherwise) between two plants, but all progeny whose pedigree tracesback to the original cross. In one aspect of the present invention, theprogeny contain about 50%, 25%, 12.5% or less nuclear DNA from a PowderyMildew resistant pepper plant and expresses the genetic material thatprovides Powdery Mildew resistance. Representative populations of pepperplants comprising progeny having resistance to Powdery Mildew includeprogeny of the cross of susceptible parent SBY 99-1179 X resistantparent PBC167.

One embodiment of the present invention provides for a Powdery Mildewresistant pepper plant that contains a genetic marker linked to one ormore Powdery Mildew resistance locus or loci. By “Powdery Mildewresistance locus” is meant a locus that contributes to Powdery Mildewresistance either alone or in combination with one or more other PowderyMildew resistance locus or loci. By “contributes to Powdery Mildewresistance” it is meant that the degree of Powdery Mildew resistance isincreased in the corresponding plant, either when the locus is alone orin combination with one or more other locus or loci.

In one embodiment of the invention, a marker linked to one or morePowdery Mildew resistance loci includes one or more of the following:NE0235653, NE0238847, NE0237736, NE0236986, NE0236080, NE0237755,NE0239177, NE0238603, NE0238046, NE0237823, NE0230886, NE0240044,NE0237442, NE0238362, NE0238536, NE0236808, NE0238448, NE0241383,NE0240496, NE0237841, NE0239164, NE0240741, NE0236790, NE0238624,NE0240275, NE0238899, NE0238734, NE0240256, NE0237985, NE0239638,NE0239147, NE0240589, NE0237975, NE0239291, NE0235654, NE0238449,NE0240786, NE0239990, NE0231151, NE0240438, NE0237121, NE0238426,NE0235272, NE0237901, NE0237351, NE0241057, NE0237348, NE0240958,NCANN005704058, NCANN005704056, NCANN005704052, and NCANN005704049,comprising a single nucleotide polymorphism of one of SEQ ID NOs:1-44.

As used herein, linkage of two nucleic acid sequences, including anucleic acid marker sequence and a nucleic acid sequence of a geneticlocus imparting a desired trait such as Powdery Mildew resistance, maybe genetic or physical or both. In one aspect of the invention, thenucleic acid marker and genetic locus conferring Powdery Mildewresistance are genetically linked, and exhibit a LOD score of greaterthan 2.0, as judged by interval mapping for the Powdery Mildewresistance trait based on maximum likelihood methods described by Landerand Botstein, 1989 (Genetics, 121:185-199), and implemented in thesoftware package MAPMAKER (e.g. Lander et al., Genomics 1:174-181,(1987); default parameters). Alternatively, other software such as QTLCartographer v1.17 (Basten et al., Zmap-a QTL cartographer. In:Proceedings of the 5th World Congress on Genetics Applied to LivestockProduction: Computing Strategies and Software, edited by C. Smith, J. S.Gavora, B. Benkel, J. Chesnais, W. Fairfull, J. P. Gibson, B. W. Kennedyand E. B. Burnside. Volume 22, pages 65-66. Organizing Committee, 5thWorld Congress on Genetics Applied to Livestock Production, Guelph,Ontario, Canada, 1994; and Basten et al., QTL Cartographer, Version1.17. Department of Statistics, North Carolina State University,Raleigh, N.C., 2004) may be used. Mapping of QTL is well-described (e.g.WO 90/04651; U.S. Pat. Nos. 5,492,547, 5,981,832, 6,455,758; reviewed inFlint-Garcia et al. 2003 (Ann. Rev. Plant Biol. 54:357-374, thedisclosures of which are hereby incorporated by reference). In otherembodiments, the marker and region conferring Powdery Mildew resistanceare genetically linked and exhibit a LOD score of greater than 3.0, or aLOD score of greater than 6.0, 9.0, 12.0, 15.0, or 18.0. In oneembodiment, the marker and region contributing to Powdery Mildewresistance are genetically linked and exhibit a LOD score of betweenabout 14 and about 20. When assigning the presence of a QTL, the LODthreshold score associated with a QTL analysis as described herein maybe determined to be significant at the 95% confidence level, or higher,such as at the 98% or 99% confidence level.

In another aspect, the nucleic acid marker is genetically linked at adistance of between about 0 and about 50 cM to the Powdery Mildewresistance locus. In other embodiments, the distance between the nucleicacid marker and the Powdery Mildew resistance locus is between about 0and about 35 cM, or between about 0 and about 25 cM, or between about 0and about 15 cM, or between about 0 and about 10 cM, or between about 0and about 5 cM, including less than about 4, 3, 2 or 1 cM.

In yet another aspect, the invention provides a pepper plant comprisingan introgressed chromosomal region from chromosome 4 of PBC167 or aprogeny plant thereof, of about 40 cM or less within the region definedas spanning the positions of SNP marker NE0235653 and SNP markerNE0240958; or SNP marker NE0235653 and SNP marker NE0237348.

In another aspect, the nucleic acid marker sequence may be physicallylinked to a Powdery Mildew resistance locus. In some aspects, thenucleic acid sequence of the genetic marker specifically hybridizes to anucleic acid molecule having a sequence that is within about 100 Mbp, orabout 80 Mbp, or about 75 Mbp, or about 70 Mbp, or about 65 Mbp of aPowdery Mildew resistance locus. In another aspect, the nucleic acidsequence of the genetic marker specifically hybridizes to a nucleic acidmolecule having a sequence of any of SEQ ID NOs:1-44, or a complementthereof.

As used herein, two nucleic acid molecules are said to be capable ofhybridizing to one another if the two molecules are capable of formingan anti-parallel, double-stranded nucleic acid structure. Conventionalstringency conditions are described by Sambrook et al., MolecularCloning, A Laboratory Manual, 2nd Ed., Cold Spring Harbor Press, ColdSpring Harbor, N.Y. (1989) and by Haymes et al., Nucleic AcidHybridization, A Practical Approach, IRL Press, Washington, D.C. (1985).Departures from complete complementarity are therefore permissible, aslong as such departures do not completely preclude the capacity of themolecules to form a double-stranded structure. Thus, in order for anucleic acid molecule to serve as a primer or probe it need only besufficiently complementary in sequence to be able to form a stabledouble-stranded structure under the particular solvent and saltconcentrations employed.

Appropriate stringency conditions which promote DNA hybridization, forexample, 6.0× sodium chloride/sodium citrate (SSC) at about 45° C.,followed by a wash of 2.0×SSC at 50° C., are known to those skilled inthe art or can be found in Current Protocols in Molecular Biology, JohnWiley & Sons, N.Y. (1989), 6.3.1-6.3.6. In some embodiments,hybridization conditions can be high, moderate or low stringencyconditions. Preferred conditions include those using 50% formamide,5.0×SSC, 1% SDS and incubation at 42° C. for 14 hours, followed by awash using 0.2×SSC, 1% SDS and incubation at 65° C.

The specificity of hybridization can be affected by post-hybridizationwashes. For example, the salt concentration in the wash step can beselected from a low stringency of about 2.0×SSC at 50° C. to a moderatestringency of about 1.0×SSC at 50° C. to a high stringency of about0.2×SSC at 50° C. In addition, the temperature in the wash step can beincreased from low stringency conditions at room temperature, about 22°C., to moderate stringency conditions at about 50° C., to highstringency conditions at about 65° C. Both temperature and saltconcentration may be varied, or either the temperature or the saltconcentration may be held constant while the other variable is changed.In some aspects, the wash step can be performed for 5, 10, 15, 20, 25,30, or more minutes. In another aspect, the wash step is performed forabout 20 minutes. In yet another aspect, the wash step can be repeated1, 2, 3, 4, or more times using the selected salt concentration,temperature, and time. In another aspect, the wash step is repeatedtwice.

A genetic marker profile of a plant may be predictive of the agronomictraits of a hybrid produced using that inbred. For example, if an inbredplant of known genetic marker profile and phenotype is crossed with asecond inbred of known genetic marker profile and phenotype it ispossible to predict the phenotype of the F1 hybrid based on the combinedgenetic marker profiles of the parent inbreds. Methods for prediction ofhybrid performance from genetic marker data are disclosed in U.S. Pat.No. 5,492,547, the disclosure of which is specifically incorporatedherein by reference in its entirety. Such predictions may be made usingany suitable genetic marker, for example, SSRs, INDELs, RFLPs, AFLPs,SNPs, ISSRs, or isozymes.

Additional markers, such as SSRs, AFLP markers, RFLP markers, RAPDmarkers, phenotypic markers, SNPs, isozyme markers, or microarraytranscription profiles that are genetically linked to or correlated withPowdery Mildew resistance can be utilized (Walton, Seed World 22-29(July, 1993); Burow and Blake, Molecular Dissection of Complex Traits,13-29, Eds. Paterson, CRC Press, New York (1988)). Methods to isolatesuch markers and to design probes or primers useful in following thepresence of such markers are known in the art. For example,locus-specific SSRs can be obtained by screening a pepper genomiclibrary for SSRs, sequencing of “positive” clones, designing primerswhich flank the repeats, and amplifying genomic DNA with these primers.Likewise, SNP markers may be identified as well.

The genetic linkage of marker molecules to Powdery Mildew resistance canbe established by a gene mapping model such as, without limitation, theflanking marker model, and interval mapping, based on maximum likelihoodmethods described by Lander and Botstein, 1989 (Genetics, 121:185-199),and implemented in the software packages MAPMAKER (Whitehead Institutefor Biomedical Research, Cambridge Mass., USA) or QTL Cartographer(North Carolina State University, Bioinformatics Research Center) or thelike. A maximum likelihood estimate (MLE) for the presence of a markeris calculated, together with an MLE assuming no trait effect, to avoidfalse positives. A log 10 of an odds ratio (LOD) is then calculated as:LOD=log 10 (MLE for the presence of a trait (MLE given no linkedtrait)).

The LOD score essentially indicates how much more likely the data are tohave arisen assuming the presence of a resistance allele rather than inits absence. The LOD threshold value for avoiding a false positive witha given confidence, say 95%, depends on the number of markers and thelength of the genome. Graphs indicating LOD thresholds are set forth inLander and Botstein (1989), and further described by Ars andMoreno-Gonzalez, Plant Breeding, Hayward, Bosemark, Romagosa (eds.)Chapman & Hall, London, pp. 314-331 (1993), and van Ooijen (Heredity83:613-624, 1999).

Selection of appropriate mapping or segregation populations is importantin trait mapping. The choice of appropriate mapping population dependson the type of marker systems employed (Tanksley et al., Molecularmapping plant chromosomes. Chromosome structure and function: Impact ofnew concepts J. P. Gustafson and R. Appels (eds.), Plenum Press, NewYork, pp. 157-173 (1988)). Consideration must be given to the source ofparents (adapted vs. exotic) used in the mapping population. Chromosomepairing and recombination rates can be severely disturbed (suppressed)in wide crosses (adapted×exotic) and generally yield greatly reducedlinkage distances. Wide crosses will usually provide segregatingpopulations with a relatively large array of polymorphisms when comparedto progeny in a narrow cross (adapted×adapted).

Advanced breeding lines are collected from breeding programs. These aretested for their phenotype (e.g. their disease score reactions toPowdery Mildew infection), and genotyped for markers in the PowderyMildew QTL intervals. From these data, the smallest genetic interval isidentified within each QTL containing the donor parent (DP) favorableallele among the Powdery Mildew resistant lines. This interval isinferred to be critical for conferring resistance to Powdery Mildew.Candidate genetic intervals associated with Powdery Mildew resistancewere detected as regions showing enhanced frequency of the favorableallele from the Powdery Mildew resistance donor PBC167 relative to abaseline set of Powdery Mildew susceptible samples from the samegermplasm classification type (GCT). For example, comparisons may bemade among Powdery Mildew resistant and susceptible inbreds within asingle GCT and a single breeding program. Allele frequency shiftsbetween phenotypic classes may be detected by calculating a linkageassessment score (LAS) as: LAS=(Frequency of favorable allele in sampleswith favorable phenotype)×(Frequency of unfavorable allele in sampleswith unfavorable phenotype).

As used herein, the progeny include not only, without limitation, theproducts of any cross (be it a backcross or otherwise) between twoplants, but all progeny whose pedigree traces back to the originalcross. Specifically, without limitation, such progeny include plantsthat have 50%, 25%, 12.5% or less nuclear DNA derived from one of thetwo originally crossed plants. As used herein, a second plant is derivedfrom a first plant if the second plant's pedigree includes the firstplant.

The present invention provides a genetic complement of the pepper linesdescribed herein. Further provided is a hybrid genetic complement,wherein the complement is formed by the combination of a haploid geneticcomplement from elite inbred pepper lines described herein and anotherhaploid genetic complement. Means for determining such a geneticcomplement are well-known in the art.

As used herein, the phrase “genetic complement” means an aggregate ofnucleotide sequences, the expression of which defines the phenotype of aplant, such as a pepper plant of the genus Capsicum or a cell or tissueof that plant. By way of example, a pepper plant of the genus Capsicumis genotyped to determine a representative sample of the inheritedmarkers it possesses. Markers are preferably inherited in codominantfashion so that the presence of both alleles at a diploid locus arereadily detectable, and they are free of environmental variation, i.e.,their heritability is close to, or equal to, 1. This genotyping ispreferably performed on at least one generation of the descendant plantfor which the numerical value of the trait or traits of interest arealso determined. The array of single locus genotypes is expressed as aprofile of marker alleles, two at each locus for a diploid plant. Themarker allelic composition of each locus can be either homozygous orheterozygous. Homozygosity is a condition where both alleles at a locusare characterized by the same conditions of the genome at a locus (e.g.,the same nucleotide sequence). Heterozygosity refers to differentconditions of the genome at a locus. Potentially any type of geneticmarker could be used, for example, simple sequence repeats (SSRs),insertion/deletion polymorphism (INDEL), restriction fragment lengthpolymorphisms (RFLPs), amplified fragment length polymorphisms (AFLPs),single nucleotide polymorphisms (SNPs), and isozymes.

Considerable genetic information can be obtained from a completelyclassified F2 population using a codominant marker system (Mather,Measurement of Linkage in Heredity: Methuen and Co., (1938)). An F2population is the first generation of self or sib pollination after thehybrid seed is produced. Usually a single F1 plant is self or sibpollinated to generate a population segregating for the nuclear-encodedgenes in a Mendelian (1:2:1) fashion.

In contrast to the use of codominant markers, using dominant markersoften requires progeny tests (e.g., F3 or back cross self families) toidentify heterozygous individuals. The information gathered can beequivalent to that obtained in a completely classified F2 population.This procedure is, however, often prohibitive because of the cost andtime involved in progeny testing. Progeny testing of F2 individuals isoften used in map construction where error is associated with singleplant phenotyping, or when sampling the plants for genotyping affectsthe ability to perform accurate phenotyping, or where trait expressionis controlled by a QTL. Segregation data from progeny test populations(e.g., F3 or backcrossed or selfed families) can be used in traitmapping. Marker-assisted selection can then be applied to subsequentprogeny based on marker-trait map associations (F2, F3), where linkagehas not been completely disassociated by recombination events (i.e.,maximum disequilibrium).

Recombinant inbred lines (RILs) (genetically related lines; usually >F5)can be used as a mapping population. RILs can be developed by selfing F2plants, then selfing the resultant F3 plants, and repeating thisgenerational selfing process, thereby increasing homozygosity.Information obtained from dominant markers can be maximized by usingRILs because all loci are homozygous or nearly so. Under conditions oftight linkage (i.e., about <10% recombination), dominant and co-dominantmarkers evaluated in RIL populations provide more information perindividual than either marker type in backcross populations (e.g. Reiteret al., 1992; Proc. Natl. Acad. Sci. (U.S.A.) 89:1477-1481). However, asthe distance between markers becomes larger (i.e., loci become moreindependent), the information in RIL populations decreases dramaticallywhen compared to codominant markers.

Backcross populations can be utilized as mapping populations. Abackcross population (BC) can be created by crossing an F1 to one of itsparents. Typically, backcross populations are created to recover thedesirable traits (which may include most of the genes) from a recurrentparental line (the parent that is employed in the backcrosses) whileadding one or a few traits from the second parental line, which is oftenreferred to as the donor. A series of backcrosses to the recurrentparent can be made to recover most of the recurrent parent's desirabletraits. Thus a population is created consisting of individuals nearlylike the recurrent parent, wherein each individual carries varyingamounts or a mosaic of genomic regions from the donor parent. Backcrosspopulations can be useful for mapping dominant markers particularly ifall loci in the recurrent parent are homozygous and the donor andrecurrent parent have contrasting polymorphic marker alleles (Reiter etal., 1992; Proc. Natl. Acad. Sci. (U.S.A.) 89:1477-1481).

Information obtained from backcross populations using either codominantor dominant markers is less than that obtained from completelyclassified F2 populations because recombination events involving one,rather than two, gametes are sampled per plant. Backcross populations,however, are more informative (at low marker saturation) when comparedto RILs as the distance between linked loci increases in RIL populations(i.e., about 15% recombination). Increased recombination can bebeneficial for resolution of tight linkages, but may be undesirable inthe construction of maps with low marker saturation.

Near-isogenic lines (NIL) created by many backcrosses to produce anarray of individuals that are nearly identical in genetic compositionexcept for the trait or genomic region under interrogation can be usedas a mapping population. In mapping with NILs, only a portion of theloci polymorphic between the parental lines are expected to segregate inthe highly homozygous NIL population. Those loci that are polymorphic ina NIL population, however, are likely to be linked to the trait ofinterest.

Bulk segregant analysis (BSA) is a method developed for the rapididentification of linkage between markers and traits of interest(Michelmore, et al., 1991; Proc. Natl. Acad. Sci. (U.S.A.)88:9828-9832). In BSA, two bulk DNA samples are drawn from a segregatingpopulation originating from a single cross. These bulk samples containindividuals that are identical for a particular trait (e.g., resistantor susceptible to a particular pathogen) or genomic region but arbitraryat unlinked regions (i.e., heterozygous). Regions unlinked to the targettrait will not differ between the bulked samples of many individuals inBSA.

In another aspect, the present invention provides a method of producinga Powdery Mildew resistant pepper plant comprising: (a) crossing apepper line having Powdery Mildew resistance with a second pepper linelacking Powdery Mildew resistance to form a segregating population; (b)screening the population for resistance to Powdery Mildew; and (c)selecting one or more members of the population having said PowderyMildew resistance. In one aspect, the pepper line having Powdery Mildewresistance is crossed with the second pepper line for at least twogenerations (e.g., creating either an F2 or BC1S1 population). In aparticular embodiment, the pepper line having Powdery Mildew resistanceis PBC167, or a progeny thereof. In another aspect, plants areidentified as Powdery Mildew resistant prior to crossing. In one aspect,plants can be selected on the basis of partial or complete resistance toPowdery Mildew. In one aspect, the segregating population isself-crossed and the subsequent population is screened for resistance.

In another aspect, the present invention provides a method ofintrogressing Powdery Mildew resistance into a pepper plant comprising:(a) crossing at least a first pepper line having Powdery Mildewresistance with a second pepper line to form a segregating population;(b) screening said population for resistance to Powdery Mildew; and (c)selecting at least one member of said population exhibiting PowderyMildew resistance. In one aspect, the pepper line having Powdery Mildewresistance is crossed with the second pepper line for at least twogenerations (e.g., creating either an F2 or BC1S1 population), or up to2-10 generations. In another aspect, plants are identified as PowderyMildew resistant prior to crossing. In one aspect, the segregatingpopulation is self-crossed and the subsequent population is screened forresistance.

Pepper plants (and parts thereof, including seed, pollen, and ovules)generated using a method of the present invention are also provided, andcan be part of or generated from a breeding program. The choice ofbreeding method depends on the mode of plant reproduction, theheritability of the trait(s) being improved, and the type of cultivarused commercially (e.g., F1 hybrid cultivar, pure line cultivar, etc).Selected, non-limiting approaches for breeding the plants of the presentinvention are set forth below. A breeding program can be enhanced usingmarker assisted selection of the progeny of any cross. It is furtherunderstood that any commercial and non-commercial cultivars can beutilized in a breeding program. Factors such as, for example, emergencevigor, vegetative vigor, stress tolerance, disease resistance,branching, flowering, fruit size, fruit quality, and/or fruit yield willgenerally dictate the choice.

For highly heritable traits, a choice of superior individual plantsevaluated at a single location will be effective, whereas for traitswith low heritability, selection should be based on statistical analyses(e.g., mean values) obtained from replicated evaluations of families ofrelated plants. Popular selection methods commonly include pedigreeselection, modified pedigree selection, mass selection, and recurrentselection. In a preferred embodiment a backcross or recurrent breedingprogram is undertaken.

The complexity of inheritance influences choice of the breeding method.Backcross breeding can be used to transfer one or a few favorable genesfor a highly heritable trait into a desirable cultivar. This approachhas been used extensively for breeding disease-resistant cultivars.Various recurrent selection techniques are used to improvequantitatively inherited traits controlled by numerous genes. The use ofrecurrent selection in self-pollinating crops depends on the ease ofpollination, the frequency of successful hybrids from each pollination,and the number of hybrid offspring from each successful cross.

Breeding lines can be tested and compared to appropriate standards inenvironments representative of the commercial target area(s) for two ormore generations. The best lines are candidates as parents for newcommercial cultivars; those still deficient in traits may be used asparents for hybrids, or to produce new populations for furtherselection.

One method of identifying a superior plant is to observe its performancerelative to other experimental plants and to a widely grown standardcultivar. If a single observation is inconclusive, replicatedobservations can provide a better estimate of its genetic worth. Abreeder can select and cross two or more parental lines, followed byrepeated self or sibling pollination and selection, producing many newgenetic combinations.

The development of new pepper lines requires the development andselection of pepper varieties, the crossing of these varieties andselection of superior hybrid crosses. The hybrid seed can be produced bymanual crosses between selected male-fertile parents or by using malesterility systems. Hybrids can be selected for certain single genetraits such as flower color, seed yield or herbicide resistance thatindicate that the seed is truly a hybrid. Additional data on parentallines, as well as the phenotype of the hybrid, influence the breeder'sdecision whether to continue with the specific hybrid cross.

Pedigree breeding and recurrent selection breeding methods can be usedto develop cultivars from breeding populations. Breeding programscombine desirable traits from two or more cultivars or variousbroad-based sources into breeding pools from which cultivars aredeveloped by selfing and selection of desired phenotypes into parentlines. These lines are used to produce new cultivars. New cultivars canbe evaluated to determine which have commercial potential.

Pedigree breeding is used commonly for the improvement ofself-pollinating crops. Two parents who possess favorable, complementarytraits are crossed to produce an F1. An F2 population is produced byselfing one or several F1's. Selection of the best individuals in thebest families is performed. Replicated testing of families can begin inthe F4 generation to improve the effectiveness of selection for traitswith low heritability. At an advanced stage of inbreeding (i.e., F6 andF7), the best lines or mixtures of phenotypically similar lines aretested for potential release as new cultivars.

Backcross breeding and cross breeding have been used to transfer genesfor a simply inherited, highly heritable trait into a desirablehomozygous cultivar or inbred line, which is the recurrent parent. Thesource of the trait to be transferred is called the donor parent. Theresulting plant obtained from a successful backcrossing program isexpected to have the attributes of the recurrent parent (e.g., cultivar)and the desirable trait transferred from the donor parent. After theinitial cross, individuals possessing the phenotype of the donor parentare selected and repeatedly crossed (backcrossed) to the recurrentparent. After multiple backcrossing generations with selection, theresulting line is expected to have the attributes of the recurrentparent (e.g., cultivar) and the desirable trait transferred from thedonor parent.

Cross breeding or backcross breeding of a Powdery Mildew resistantpepper plant may be conducted where the other parent (second pepperplant) is Powdery Mildew resistant or the other parent is not PowderyMildew resistant.

Pepper plants generated of the invention may be generated using asingle-seed descent procedure. The single-seed descent procedure, in thestrict sense, refers to planting a segregating population, thenselecting one plant in this and each subsequent generation to self andcreate the next generation. When the population has been advanced fromthe F2 to the desired level of inbreeding, the plants from which linesare derived will each trace to different F2 individuals. The number ofplants in a population declines each generation due to failure of someseeds to germinate or some plants to produce at least one seed. As aresult, not all of the F2 plants originally sampled in the populationwill be represented by a progeny when generation advance is completed.

Descriptions of other breeding methods that are commonly used fordifferent traits and crops can be found in one of several availablereference books (e.g., Fehr, Principles of Cultivar Development Vol. 1,pp. 2-3 (1987)).

In one aspect of the present invention, the source of the Powdery Mildewresistance trait for use in a breeding program is derived from a plantselected from the group consisting of PBC167 and progeny pepper plantsof pepper line PBC167, such as members of the PBC167 X SBY 99-1179mapping population disclosed herein. In another aspect, the source ofthe Powdery Mildew resistance trait for use in a breeding program is notderived from a plant selected from the group consisting of PBC167 andprogeny pepper plants of pepper line PBC167, such as members of thePBC167 X SBY 99-1179 mapping population disclosed herein. Also includedin the invention is a pepper plant having a genome, wherein said genomecomprises a genetic locus conferring resistance to Powdery Mildew,wherein said genetic locus contains one or more genetic markers linkedto said genetic locus conferring resistance to Powdery Mildew, andwherein said pepper plant is not accession PBC167.

In another aspect, additional sources of Powdery Mildew resistance foruse in a breeding program can be identified by screening peppergermplasm for resistance to Powdery Mildew. In yet another aspect,pepper plants can be screened for Powdery Mildew resistance byidentifying germplasm exhibiting reduced disease symptoms relative to acontrol pepper plant after inoculation or infection. In one aspect,pepper plants can be screened for resistance to Powdery Mildew using atest such as a field or greenhouse screen and disease rating schemes asdescribed in Example 4.

In another aspect, additional sources of Powdery Mildew resistance foruse in a breeding program can be identified by screening with one ormore molecular markers linked to a genetic locus conferring resistanceto Powdery Mildew, such as those identified herein.

In another aspect, additional sources of Powdery Mildew resistance foruse in a breeding program can be identified by a combination ofscreening pepper plants for reduced disease symptoms and screening withone or more molecular markers linked to a genetic locus contributing toresistance to Powdery Mildew.

In another aspect, pepper lines having Powdery Mildew resistance can beused in breeding programs to combine Powdery Mildew resistance withadditional traits of interest. In one aspect, Powdery Mildew resistancecan be combined with any additional trait, including disease resistanttraits, yield traits, and fruit quality traits. For example, breedingprograms can be used to combine the Powdery Mildew resistance trait withalleles that contribute to size and shape in pepper fruit. Breedingprograms can also be used to combine Powdery Mildew resistance with oneor more disease resistant traits. Other disease traits includeresistance to biotic diseases caused by viroids, virus, bacteria, fungi,nematodes, and insects. Such disease resistant traits include, withoutlimitation, resistance to: Alfalfa mosaic virus, Anthracnose, BacterialCanker, Bacterial Spot, Bacterial stem and peduncle canker, BacterialWilt, Beet curly top virus, Cercospora Leaf Spot, Chaenophora Blight,Cucumber mosaic virus, Fungal root rots (Fusarium Wilt, VerticilliumWilt, Damping-off and root rot, Phytophthora Blight), Geminiviruses(Pepper golden mosaic virus, Pepper huasteco virus, Sinaloa tomato leafcurl), Gray Leaf Spot, Gray Mold, Peanut bud necrosis virus, Potato Xvirus, Potyviruses (Potato virus Y, Pepper mottle virus, Tobacco etchvirus, Pepper yellow mosaic virus, Chilli veinal mottle virus), PowderyMildew, Root-knot nematode, Southern Blight/Sclerotium Wilt, Syringaeseedling blight and leaf spot, Tobamoviruses (Tomato mosaic virus,Tobacco mosaic virus, Pepper mild mottle virus), Tospoviruses (Tomatospotted wilt virus) and White Mold (pink rot, watery soft rot).Additional traits may also include resistance to abiotic disorders suchas those caused by extremes in nutritional and environmental conditionsor other physiological disorders (e.g. Blossom-end rot). In anotheraspect, the traits that are combined can be coinherited in subsequentcrosses.

The present invention also provides for parts of the Powdery Mildewresistant pepper plants produced by a method of the present invention.Parts of pepper plants, without limitation, include plant cells or partsof plant cells, seed, endosperm, meristem, flower, anther, ovule,pollen, fruit, flowers, stems, roots, stalks or leaves, scions, and rootstocks. Plant parts also include the parts of a pepper fruit, whichinclude the placenta, columella and pericarp. In one embodiment of thepresent invention, the plant part is a seed.

The invention further provides for parts of a pepper plant having agenome, that comprises at least one genetic locus giving rise to PowderyMildew resistance in the pepper plant. One aspect of the inventionprovides a Powdery Mildew pepper plant, or the fruit or seeds thereof,wherein the pepper plant, or the fruit thereof, expresses one, or two,or three, or more independently selected desirable traits in addition toPowdery Mildew resistance. In one embodiment, the “desirable trait” or“desirable traits” are selected from the group consisting of: fruitsize, shape, color, surface appearance; seed number, seed size, loculenumber; pericarp thickness and toughness; taste and shelf life, plantvigor, leaf shape, leaf length, leaf color, plant height, whether theplant is determinate or not, time to maturity, adaptation to fieldgrowth, adaptation to greenhouse growth, and resistance to one or morediseases, disease causing organisms or physiological disorders such asAlfalfa mosaic virus, Anthracnose, Bacterial Canker, Bacterial Spot,Bacterial stem and peduncle canker, Bacterial Wilt, Beet curly topvirus, Blossom-end rot, Cercospora Leaf Spot, Chilli veinal mottlevirus, Chaenophora Blight, Cucumber mosaic virus, Damping-off and rootrot, Fungal root rots, Fusarium Wilt, Geminiviruses, Gray Leaf Spot,Gray Mold, Peanut bud necrosis virus, Pepper golden mosaic virus, Pepperhuasteco virus, Pepper mild mottle virus, Pepper mottle virus, Pepperyellow mosaic virus, Phytophthora Blight, Potato X virus, Potato Yvirus, Powdery Mildew, Root-knot nematode, Sinaloa tomato leaf curl,Southern Blight/Sclerotium wilt, Syringae seedling blight and leaf spot,Tobacco etch virus, Tobacco mosaic virus, Tobamoviruses, Tomato mosaicvirus, Tomato spotted wilt virus, Tospoviruses, Verticillium Wilt andWhite Mold (pink rot, watery soft rot). In another embodiment the“desirable trait” or “desirable traits” are selected from the groupconsisting of: fruit size, fruit shape, fruit color, fruit qualityacceptable to market, and the shelf life of fruit.

In other aspects of the invention, the plants bearing one or moredesirable traits in addition to Powdery Mildew resistance display agreater than 10%, or a greater than 30%, or a greater than 60%, or agreater than 80% reduction in Leveillula taurica sporulation relative toa non-resistant control plant upon inoculation or infection with PowderyMildew. Another aspect of the present invention is directed to a methodof producing a Powdery Mildew resistant pepper plant comprising:crossing a pepper line having Powdery Mildew resistance with a secondplant lacking Powdery Mildew resistance but capable of donating one ormore of the aforementioned desirable traits.

EXAMPLES

The following examples are included to demonstrate preferred embodimentsof the invention. It should be appreciated by those of skill in the artthat the techniques disclosed in the examples which follow representtechniques discovered by the inventor to function well in the practiceof the invention, and thus can be considered to constitute preferredmodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or similar result without departing from the spirit and scope ofthe invention.

Example 1 Identification of Resistance to Pepper Powdery Mildew Causedby Leveillula taurica

To identify germplasm exhibiting resistance to Powdery Mildew caused bythe fungus Leveillula taurica, a screen was undertaken with germplasmunder disease pressure conditions. A line derived from PBC167 wasidentified in this screen as a source of resistance to Leveillulataurica. PBC167 is available from the United States Department ofAgriculture (USDA) germplasm collection under PI640507. In order todevelop tools with which to track this PBC167-derived Leveillula tauricaresistance, an association mapping analysis was undertaken.

Example 2 Development of a Mapping Population

A population was developed to create linkage and QTL maps. The pepperline PBC167 displays resistance to Leveillula taurica. Pepper line SBY99-1179 is susceptible to Powdery Mildew caused by the fungus Leveillulataurica. In SBY 99-1179, introgression of PBC167-derived sequenceeffects the resistance response. Plants derived from crosses betweenthese pepper lines with distinct levels of Leveillula taurica resistancewere obtained, and certain resulting lines were genotyped and phenotypedfor association mapping analysis.

Example 3 Identification of Leveillula taurica Resistance MappingPopulation Genotypes

The BC1 generation (n=87) of the mapping population from Example 2 wasgenotyped at a selection of SNP markers collectively spanning eachchromosome in the plant genome.

Example 4 Mapping Population Leveillula taurica Disease-ResponsePhenotyping

Corresponding progenies (BC1F2; n=96) of the population genotyped inExample 3 were evaluated for Leveillula taurica resistance undergreenhouse bioassay conditions. In the greenhouse in Woodland, Calif.,plants were inoculated at the 3-4 true leaf stage, approximately 20 dayspost seedling. Plants were organized in a randomized block design. Usinga spray bottle with 1×10⁴ c/mL of conidia in reverse osmosis purifiedwater, plants were sprayed uniformly on the foliage of all plants untilrunoff. Prior to inoculum preparation, a locally collected Leveillulataurica strain was maintained on the susceptible host Yolo Wonder B.After allowing infection to develop, plants were scored on a three pointscale of 1 (resistant) to 9 (susceptible).

The following rating scale definitions were used to characterize thegreenhouse trial:

-   -   a. 1 (Resistant): No sporulation    -   b. 5 (Intermediate Resistance): Very light sporulation usually        underneath the leaf    -   c. 9 (Susceptible): White sporulation on the whole surface of        inoculated leaves

The same BC1F2 families were also evaluated under field conditions whereprogenies (n=100) were evaluated for Powdery Mildew resistance in afield in Woodland, Calif. after allowing disease pressure to developnaturally. The trial was set in a randomized block design with 3replications. Each plot consisted of >10 plants. All plants in each plotwere scored on a three point scale of 1 (resistant) to 9 (susceptible).

The following rating scale definitions were used to characterize thefield trial:

-   -   d. 1 (Resistant): No sporulation    -   e. 5 (Intermediate Resistance): Very light sporulation usually        underneath the leaf    -   f. 9 (Susceptible): White sporulation on the whole surface of        inoculated leaves

Progenies (n=96) were additionally evaluated for Powdery Mildewresistance in greenhouse and field conditions in Almeria, Spain withisolates from that region. For greenhouse bioassay evaluation, pepperplants were grown in rock wool and distributed on a table with a layerof soil, leaving around 7-8 cm between rock wools. The soil was watereddaily, without splashing the pepper plants. The humid layer of soilhelps to obtain the necessary relative humidity (RH) for the assay.Inoculation was carried out at the growth stage of 4 fully grown leavesby spraying a conidia suspension as described: Inoculum of the funguswas collected from an infected greenhouse by picking leaves withabundant white powdery mildew sporulation. Conidia were obtained fromleaves on the day of inoculation by washing the symptomatic leaves withthe aid of a fine brush, followed immediately by dilution to 4×104conidia/ml with a Bürker Türk haemocytometer. The conidia suspension wasfiltered through cheesecloth to remove plant material. For theinoculation, the lower side of the leaves was sprayed with conidiasuspension. Inoculations were performed in the late afternoon, avoidingpeak temperatures, and a high soil moisture status was maintained. Afterinoculation, plants were allowed to develop symptom expression in atemperature/humidity-controlled greenhouse environment (Night 18° C.-Day22° C. and 65%-80% HR). Evaluation of symptoms was assessed based onsporulation density and number of spots per leaf at 25-30 days postinoculation (dpi) according to a scale from 0 to 5 as follows:

Density of sporulation: Spot per leaf: 0 = no visible sporulation 0 = Nospots 1 = few spores per spot, <10% 1 = 1 or 2 spots 2 = lightsporulation, 25% 2 = 3, 4 or 5 spots 3 = strong sporulation, easy to see25-50% 3 = more than 5 spots per leaf 4 = very strong sporulation 50-75%4 = 50% of leaf affected 5 = sporulation on upper and lower side of leaf5 = 90% of leaf affected

Example 5 QTL Mapping

Single Marker Regression:

The R/qtl function scanone (method=mr) was used to scan for single QTLacross the whole genome. Genome wide 1000 permutations were generatedand a 5% false discovery rate was utilized as a significance threshold.One QTL on Chromosome 4 was detected with this threshold. Two QTLmarkers were identified by this methodology as being significantlylinked to the QTL (Table 2).

TABLE 2 QTL Linked Markers identified by Marker Regression. LOD MarkerWld_GH Wld_Fld Spain_GH Spain_Fld Chr Threshold 5% 3.12 3.49 3.18 3.2NE0236790 51.9 13.7 38.1 19.1 4 NE0237985 49.4 13.7 32.1 18.6 4 WhereWld = Woodland, California; Spain = Almeria, Spain; GH = greenhouse; andFld = field.

Interval Mapping:

A non-parametric mapping model was adopted for QTL identification.Interval mapping using this non-parametric model was performed foradjusted phenotypic data at 1 cM intervals. LOD score significance wasbased on the 5% alpha threshold obtained with 1,000 permutationsgenome-wide.

A QTL was identified by all four sets of phenotypic data at almost thesame location on chromosome 4 (Table 3 and FIGS. 1-2). Effects ofmarkers associated with the QTL 2-LOD interval region are listed inTable 4.

TABLE 3 QTL identified by interval mapping. Max LOD Threshold 1-LOD2-LOD 3-LOD Max Position Phenotype (5% FDR) (cM) (cM) (cM) LOD (cM) LeftMRN Right MRN Wld_GH 2.88 14.1-32.7 11.7-39.7  7.7-40.7 13.4 23.7NE0236790 NE0237985 Wld_Fld 2.75 16.7-26.7 11.7-37.6  7.7-42.7 7.17 23.7NE0236790 NE0237985 Spain_GH 2.87 17.7-26.7 15.7-38.7 14.1-40.7 13.621.6 NE0236808 NE0237985 Spain_Fld 2.82 15.7-26.7 12.7-39.7 11.7-41.712.1 23.7 NE0236790 NE0237985 Where FDR = false discovery rate; and MRN= marker number.

TABLE 4 Effects of Markers within QTL 2-LOD Interval Region. PositionEffects MRN Chr (cM) Wld_GH Wld_Fld Spain_GH Spain_Fld NE0237823 4 11.6−3.6 −3.3 −2.3 −1.7 NE0237442 4 13.4 −3.8 −3.4 −2.6 −1.9 NE0236808 414.1 −3.8 −3.4 −2.6 −1.9 NE0238624 4 21.6 −4.1 −3.9 −2.8 −2.0 NE02367904 21.6 −4.1 −3.9 −2.8 −2.0 NE0237985 4 25.2 −4.1 −3.9 −2.8 −2.0NE0239147 4 26.8 −4.0 −3.6 −2.7 −1.9 NE0240438 4 37.6 −3.9 −3.4 −2.6−1.9 NE0237348 4 45.3 −2.8 −2.6 −2.0 −1.4

Example 7 Segregation Ratio Confirms QTL Mapping Results

When looking at resistant vs. susceptible, the segregation ratio fitswith a one dominant gene model (Table 5). This supports the single locusdominant inheritance and large QTL effect of Powdery Mildew resistancederived from PBC167 based on F2 and BC1 data (Table 5).

TABLE 5 Chi-square test of Fit for Single Dominant gene model of PowderyMildew resistance in PBC167 derived BC1F2, after combining homozygousand heterozygous resistant plants into one group. BC1F2 ObservedExpected R (3/8) 37 36 S (5/8) 59 60 total 96 96 X² 0.044444 p-value>0.50

TABLE 6 Chi-square analysis of Fit for Single Dominant gene model ofPowdery Mildew resistance in PBC167. Total Chi- plants expected Sexpected R observed S observed R square p-value F2 246 61.5 184.5 48 1983.951 0.0468 F2 (3:1) BC1 244 122 122 134 110 2.361 0.1244 BC1F1 (1:1)

Example 8 Alignment of Mapped QTL Region to Pepper Consensus Map AllowsIdentification of Additional Markers Linked to the Region ConferringResistance to Pepper Powdery Mildew Caused by Leveillula taurica

Markers associated with Powdery Mildew resistance and used for QTLmapping can be additionally placed on a pepper consensus map to locateadditional markers associated with the QTL region on Chromosome 4 thatconfers resistance to pepper Powdery Mildew caused by Leveillulataurica. On pepper chromosome 4, approximate map position relative toother markers, in cM, is given where position 0 is the most distalmarker known at the beginning of the chromosome (Table 7).

TABLE 7 Exemplary additional markers linked to QTL. MRN ChromosomePosition (cM) NE0235653 4 7.131 NE0238847 4 8.152 NE0237736 4 8.631NE0236986 4 9.093 NE0236080 4 9.158 NE0237755 4 10.125 NE0239177 410.125 NE0238603 4 10.893 NE0238046 4 11.063 NE0237823 4 11.565NE0230886 4 12.049 NE0240044 4 12.049 NE0237442 4 13.390 NE0238362 413.416 NE0238536 4 13.910 NE0236808 4 14.110 NE0238448 4 14.110NE0241383 4 14.110 NE0240496 4 14.788 NE0237841 4 16.764 NE0239164 418.190 NE0240741 4 18.611 NE0236790 4 21.562 NE0238624 4 21.562NE0240275 4 21.562 NE0238899 4 24.871 NE0238734 4 24.872 NE0240256 425.108 NE0237985 4 25.173 NE0239638 4 25.885 NE0239147 4 26.810NE0240589 4 29.496 NE0237975 4 30.808 NE0239291 4 31.511 NE0235654 431.598 NE0238449 4 34.387 NE0240786 4 34.387 NE0239990 4 34.844NE0231151 4 37.409 NE0240438 4 37.571 NE0237121 4 38.234 NE0238426 438.412 NE0235272 4 39.789 NE0237901 4 39.882 NE0237351 4 40.289NE0241057 4 42.610 NE0237348 4 45.269 NE0240958 4 45.269

Example 9 PBC167-Specific Marker Development

In order to obtain markers that were highly specific to PBC167, genomicDNA from PBC167 and a panel of susceptible inbred lines was resequenced.Several loci were identified that were monomorphic in the originalPBC167 mapping population. Four of these loci yielded SNPs that werehighly specific to PBC167 in a larger accuracy panel of 100+ inbreds(Table 8). The original four loci (NE0239291, NE0240589, NE0239638,NE0240275) were given derived-marker numbers to reflect the new SNPsfrom those amplicons. These new SNPs are highly-predictive of PBC167.

TABLE 8 PBC167-specific SNPs on chromosome 4. Position Hetero- Par- MRNDerived-MRN (cM) PBC167 zygote ent NE0239291 NCANN005704049 31.51094 TTCT CC NE0240589 NCANN005704052 29.49618 CC AC AA NE0239638NCANN005704056 25.88461 CC CT TT NE0240275 NCANN005704058 21.56184 GG AGAA

All publications and patent applications cited herein are incorporatedby reference to the same extent as if each individual publication orpatent application was specifically and individually indicated to beincorporated by reference.

Although certain embodiments have been described in detail above, thosehaving ordinary skill in the art will clearly understand that manymodifications are possible in the embodiments without departing from theteachings thereof. All such modifications are intended to be encompassedwithin the invention as disclosed.

What is claimed is:
 1. An agronomically elite pepper plant comprising atleast a first introgressed chromosomal interval conferring resistance toPowdery Mildew, wherein the interval is a Powdery Mildew resistancecontributing QTL on pepper chromosome 4 between markers NCANN005704058and NCANN005704049, wherein said QTL is present in pepper line PBC167,wherein said QTL comprises markers NCANN005704058, NCANN005704056,NCANN005704052, and NCANN005704049.
 2. The pepper plant of claim 1,which displays a trait selected from the group consisting of: enhancedplant vigor, altered leaf shape, altered plant height, determinacy,altered time to maturity, increased fruit size, blocky fruit shape,tapered fruit shape, altered fruit color, altered fruit weight,increased fruit pungency, reduced fruit pungency, altered fruit taste,enhanced surface appearance; altered seed number, altered seed size,altered locule number; altered pericarp thickness and toughness,improved shelf life, enhanced fruit yield, adaptation to field growth,adaptation to greenhouse growth, and resistance to one or more diseasesor disease causing organisms.
 3. The pepper plant of claim 1, whereinthe plant is homozygous for said chromosomal interval.